Exit with EX_TEMPFAIL when watching files

Reason being that if a file disappears and it takes longer for it
to reappear than the default restart interval, the service would
just get stopped. Treat an initially missing file the same as a
file that gets deleted.

catsit-watch.c

@@ -29,7 +29,7 @@
 
 static void watch(int kq, char *path) {
 	int fd = open(path, O_RDONLY | O_CLOEXEC);
-	if (fd < 0) err(EX_NOINPUT, "%s", path);
+	if (fd < 0) err(EX_TEMPFAIL, "%s", path);
 
 	struct kevent event;
 	EV_SET(