CLEANUP: polling: rename "spec_e" to "state"

We're completely changing the way FDs will be polled. First, let's fix
a few field names which become confusing. "spec_e" was used to store a
speculative I/O event state. Now we'll store the whole R/W states for
the FD there.
diff --git a/src/ev_poll.c b/src/ev_poll.c
index 537157f..8b3f595 100644
--- a/src/ev_poll.c
+++ b/src/ev_poll.c
@@ -70,8 +70,8 @@
 	/* first, scan the update list to find changes */
 	for (updt_idx = 0; updt_idx < fd_nbupdt; updt_idx++) {
 		fd = fd_updt[updt_idx];
-		en = fdtab[fd].spec_e & 15;  /* new events */
-		eo = fdtab[fd].spec_e >> 4;  /* previous events */
+		en = fdtab[fd].state & 15;  /* new events */
+		eo = fdtab[fd].state >> 4;  /* previous events */
 
 		if (fdtab[fd].owner && (eo ^ en)) {
 			if ((eo ^ en) & FD_EV_POLLED_RW) {
@@ -87,7 +87,7 @@
 					hap_fd_set(fd, fd_evts[DIR_WR]);
 			}
 
-			fdtab[fd].spec_e = (en << 4) + en;  /* save new events */
+			fdtab[fd].state = (en << 4) + en;  /* save new events */
 
 			if (!(en & FD_EV_ACTIVE_RW)) {
 				/* This fd doesn't use any active entry anymore, we can