MEDIUM: fd: remove the FD_EV_POLLED status bit

Since commit 7ac0e35f2 in 1.9-dev1 ("MAJOR: fd: compute the new fd polling
state out of the fd lock") we've started to update the FD POLLED bit a
bit more aggressively. Lately with the removal of the FD cache, this bit
is always equal to the ACTIVE bit. There's no point continuing to watch
it and update it anymore, all it does is create confusion and complicate
the code. One interesting side effect is that it now becomes visible that
all fd_*_{send,recv}() operations systematically call updt_fd_polling(),
except fd_cant_recv()/fd_cant_send() which never saw it change.
diff --git a/doc/internals/polling-states.fig b/doc/internals/polling-states.fig
index a223016..4df9386 100644
--- a/doc/internals/polling-states.fig
+++ b/doc/internals/polling-states.fig
@@ -1,12 +1,23 @@
-#FIG 3.2
+#FIG 3.2  Produced by xfig version 3.2.7a
 Portrait
 Center
 Metric
-A4      
+A4
 100.00
 Single
 -2
 1200 2
+6 2520 990 4725 3645
+4 0 0 50 -1 16 10 0.0000 4 150 855 2520 1125 R=ready flag\001
+4 0 0 50 -1 16 10 0.0000 4 150 885 2520 1290 A=active flag\001
+4 0 0 50 -1 16 10 0.0000 4 150 1365 2520 2475 fd_want sets A flag\001
+4 0 0 50 -1 16 10 0.0000 4 150 1440 2520 2640 fd_stop clears A flag\001
+4 0 0 50 -1 16 10 0.0000 4 150 1995 2520 3465 fd_done does what's best to\001
+4 0 0 50 -1 16 10 0.0000 4 120 2025 2700 3630 minimize the amount of work.\001
+4 0 0 50 -1 16 10 0.0000 4 150 1905 2520 3300 update() updates the poller.\001
+4 0 0 50 -1 16 10 0.0000 4 150 2190 2520 2970 fd_cant clears R flag (EAGAIN)\001
+4 0 0 50 -1 16 10 0.0000 4 150 2115 2520 3135 fd_rdy sets R flag (poll return)\001
+-6
 2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
 	1 1 1.00 90.00 180.00
 	 1125 1350 1125 1800
@@ -18,97 +29,36 @@
 	 1125 3150 1125 3600
 2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
 	1 1 1.00 90.00 180.00
-	 2925 3150 2925 3600
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 2925 2250 2925 2700
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 2925 1350 2925 1800
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
 	 1575 1800 1575 1350
 2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
 	1 1 1.00 90.00 180.00
 	 1575 3600 1575 3150
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 3375 2700 3375 2250
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 3375 1800 3375 1350
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 2700 1125 1800 1125
-2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
-	1 1 1.00 90.00 180.00
-	 2700 3825 1800 3825
-2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
-	 3600 1350 2700 1350 2700 900 3600 900 3600 1350
 2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
 	 1800 1350 900 1350 900 900 1800 900 1800 1350
 2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
 	 1800 2250 900 2250 900 1800 1800 1800 1800 2250
 2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
-	 3600 2250 2700 2250 2700 1800 3600 1800 3600 2250
-2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
-	 3600 3150 2700 3150 2700 2700 3600 2700 3600 3150
-2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
-	 3600 4050 2700 4050 2700 3600 3600 3600 3600 4050
-2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
 	 1800 4050 900 4050 900 3600 1800 3600 1800 4050
 2 4 0 1 0 7 51 -1 20 0.000 0 0 7 0 0 5
 	 1800 3150 900 3150 900 2700 1800 2700 1800 3150
 2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
 	1 1 1.00 90.00 180.00
-	 1800 2925 2700 2925
+	 1350 450 1350 900
 2 1 0 1 0 7 50 -1 -1 0.000 1 0 -1 1 0 2
 	1 1 1.00 90.00 180.00
-	 1350 450 1350 900
-4 1 0 50 -1 16 8 0.0000 4 120 330 2250 1080 update\001
-4 1 0 50 -1 16 8 0.0000 4 120 330 2250 3780 update\001
-4 2 0 50 -1 16 8 0.0000 4 75 240 2880 1485 want\001
-4 0 0 50 -1 16 8 0.0000 4 105 210 3420 1755 stop\001
-4 0 0 50 -1 16 8 0.0000 4 120 585 3420 2610 poll()=>rdy\001
-4 2 0 50 -1 16 8 0.0000 4 75 210 2835 2385 cant\001
-4 2 0 50 -1 16 8 0.0000 4 90 285 2835 2655 done*\001
-4 2 0 50 -1 16 8 0.0000 4 90 255 2835 2520 wait*\001
-4 2 0 50 -1 16 8 0.0000 4 75 240 1080 1485 want\001
-4 0 0 50 -1 16 8 0.0000 4 105 210 1665 1755 stop\001
-4 0 0 50 -1 16 8 0.0000 4 90 240 1665 1620 done\001
-4 2 0 50 -1 16 8 0.0000 4 75 210 1035 2385 cant\001
-4 2 0 50 -1 16 8 0.0000 4 90 255 1035 2520 wait*\001
-4 2 0 50 -1 16 8 0.0000 4 105 210 1035 3285 stop\001
-4 0 0 50 -1 16 8 0.0000 4 75 240 1665 3510 want\001
-4 2 0 50 -1 16 8 0.0000 4 105 210 2835 3285 stop\001
-4 1 0 50 -1 16 10 0.0000 4 105 735 1350 1080 STOPPED\001
-4 1 0 50 -1 16 10 0.0000 4 105 630 3150 1080 PAUSED\001
-4 1 0 50 -1 16 10 0.0000 4 105 555 1350 1980 ACTIVE\001
-4 1 0 50 -1 16 10 0.0000 4 105 525 3150 1980 READY\001
-4 1 0 50 -1 16 10 0.0000 4 105 825 1350 2880 MUSTPOLL\001
-4 1 0 50 -1 16 10 0.0000 4 105 615 3150 2880 POLLED\001
-4 1 0 50 -1 16 10 0.0000 4 105 765 1350 3780 DISABLED\001
-4 1 0 50 -1 16 10 0.0000 4 105 525 3150 3780 ABORT\001
-4 1 0 50 -1 16 8 0.0000 4 105 360 1350 1260 R,!A,!P\001
-4 1 0 50 -1 16 8 0.0000 4 105 330 1350 2160 R,A,!P\001
-4 1 0 50 -1 16 8 0.0000 4 105 330 3150 1260 R,!A,P\001
-4 1 0 50 -1 16 8 0.0000 4 105 300 3150 2160 R,A,P\001
-4 1 0 50 -1 16 8 0.0000 4 105 330 3150 3060 !R,A,P\001
-4 1 0 50 -1 16 8 0.0000 4 105 360 1350 3060 !R,A,!P\001
-4 1 0 50 -1 16 8 0.0000 4 105 390 1350 3960 !R,!A,!P\001
-4 1 0 50 -1 16 8 0.0000 4 105 360 3150 3960 !R,!A,P\001
-4 1 0 50 -1 16 8 0.0000 4 120 330 2250 2880 update\001
-4 0 0 50 -1 16 10 0.0000 4 135 885 4275 1125 R=ready flag\001
-4 0 0 50 -1 16 10 0.0000 4 135 900 4275 1290 A=active flag\001
-4 0 0 50 -1 16 10 0.0000 4 135 915 4275 1455 P=polled flag\001
-4 0 0 50 -1 16 10 0.0000 4 135 2250 4275 1785 Transitions marked with a star (*)\001
-4 0 0 50 -1 16 10 0.0000 4 135 2505 4275 1950 are only possible with level-triggered\001
-4 0 0 50 -1 16 10 0.0000 4 135 495 4275 2115 pollers.\001
-4 0 0 50 -1 16 10 0.0000 4 135 1335 4275 2475 fd_want sets A flag\001
-4 0 0 50 -1 16 10 0.0000 4 135 1425 4275 2640 fd_stop clears A flag\001
-4 0 0 50 -1 16 10 0.0000 4 135 2340 4275 2805 fd_wait clears R flag on LT pollers\001
-4 0 0 50 -1 16 10 0.0000 4 135 1980 4275 3465 fd_done does what's best to\001
-4 0 0 50 -1 16 10 0.0000 4 105 2010 4455 3630 minimize the amount of work.\001
-4 0 0 50 -1 16 10 0.0000 4 135 1935 4275 3300 update() updates the poller.\001
-4 0 0 50 -1 16 10 0.0000 4 135 2145 4275 2970 fd_cant clears R flag (EAGAIN)\001
-4 0 0 50 -1 16 10 0.0000 4 135 2040 4275 3135 fd_rdy sets R flag (poll return)\001
+	 1575 2700 1575 2250
+4 2 0 50 -1 16 8 0.0000 4 105 270 1080 1485 want\001
+4 2 0 50 -1 16 8 0.0000 4 120 255 1035 3285 stop\001
+4 0 0 50 -1 16 8 0.0000 4 105 270 1665 3510 want\001
+4 1 0 50 -1 16 10 0.0000 4 120 735 1350 1080 STOPPED\001
+4 1 0 50 -1 16 10 0.0000 4 120 795 1350 3780 DISABLED\001
+4 1 0 50 -1 16 10 0.0000 4 120 555 1350 2880 ACTIVE\001
+4 1 0 50 -1 16 10 0.0000 4 120 540 1350 1980 READY\001
+4 0 0 50 -1 16 8 0.0000 4 90 210 1665 2565 may\001
+4 2 0 50 -1 16 8 0.0000 4 105 240 1035 2430 cant\001
+4 1 0 50 -1 16 8 0.0000 4 120 240 1350 1260 R,!A\001
+4 1 0 50 -1 16 8 0.0000 4 120 210 1350 2160 R,A\001
+4 1 0 50 -1 16 8 0.0000 4 120 240 1350 3060 !R,A\001
+4 1 0 50 -1 16 8 0.0000 4 120 270 1350 3960 !R,!A\001
+4 0 0 50 -1 16 8 0.0000 4 120 255 1665 1710 stop\001
+4 2 0 50 -1 16 8 0.0000 4 105 285 1035 2610 done\001