Fix issue #6: Segfault when stopping timer before calling uev_exit()

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

timer.c

@@ -154,12 +154,12 @@ int uev_timer_start(uev_t *w)
  */
 int uev_timer_stop(uev_t *w)
 {
-	if (uev_watcher_stop(w))
-		return -1;
-
 	/* Stop kernel timer */
 	uev_timer_set(w, 0, 0);
 
+	if (uev_watcher_stop(w))
+		return -1;
+
 	/* Close timerfd, will have to be reopened again on reset */
 	close(w->fd);
 	w->fd = -1;