Fix error handling in example callbacks

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

API.md

@@ -291,6 +291,7 @@ static void joystick_cb(uev_t *w, void *arg, int events)
         /* Possibly joystick was unplugged */
         warnx("Spurious problem with the joystick watcher, restarting.");
         uev_io_start(w);
+        return;
     }
 
     cnt = read(w->fd, &e, sizeof(e));

README.md

@@ -49,6 +49,7 @@ static void cb(uev_t *w, void *arg, int events)
         if (UEV_ERROR == events) {
             puts("Problem with timer, attempting to restart.");
             uev_timer_start(w);
+            return;
         }
 
         puts("Every other second");