BUG/MEDIUM: pollers: Clear the poll_send bits as well.

In _update_fd(), if we're about to remove the FD from the poller, remove
both the receive and the send bits, instead of removing the receive bits
twice.
diff --git a/src/ev_select.c b/src/ev_select.c
index f2a2acf..89a661c 100644
--- a/src/ev_select.c
+++ b/src/ev_select.c
@@ -57,7 +57,7 @@
 		hap_fd_clr(fd, fd_evts[DIR_RD]);
 		hap_fd_clr(fd, fd_evts[DIR_WR]);
 		_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, 0);
-		_HA_ATOMIC_AND(&polled_mask[fd].poll_recv, 0);
+		_HA_ATOMIC_AND(&polled_mask[fd].poll_send, 0);
 	}
 	else {
 		/* OK fd has to be monitored, it was either added or changed */