daemon: EINTR from kevent(2) is not a fatal error

Simply resume waiting for events rather than exiting if we took a signal
here.

This at least fixes running programs under daemon(8) in the face of
suspend/resume, which I suspect hits us with a spurious EINTR rather
than a signal anyways.

Reported and tested by:	manu
Fixes:	8935a39932 ("daemon: use kqueue for all events")

usr.sbin/daemon/daemon.c

@@ -427,6 +427,8 @@ daemon_eventloop(struct daemon_state *state)
 		ret = kevent(kq, NULL, 0, &event, 1, NULL);
 		switch (ret) {
 		case -1:
+			if (errno == EINTR)
+				continue;
 			err(EXIT_FAILURE, "kevent wait");
 		case 0:
 			continue;