style fix

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@656 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/mgt_event.c

@@ -147,7 +147,7 @@ ev_new_base(void)
 	struct evbase *evb;
 
 	evb = calloc(sizeof *evb, 1);
-	if (!evb)
+	if (evb == NULL)
 		return (evb);
 	if (ev_get_pfd(evb)) {
 		free(evb);