startup.c: free timer

Small memleak. The timer is not called used again since ev_timer_init is
called with repeat = 0.

src/startup.c

@@ -49,6 +49,7 @@ static void startup_timeout(EV_P_ ev_timer *w, int revents) {
 
     if (!sequence) {
         DLOG("Sequence already deleted, nevermind.\n");
+        free(w);
         return;
     }