We should never have an object when we hit the error state.

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@2265 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_center.c

@@ -275,6 +275,7 @@ static int
 cnt_error(struct sess *sp)
 {
 
+	AZ(sp->obj);
 	RES_Error(sp, sp->err_code, sp->err_reason);
 	sp->err_code = 0;
 	sp->err_reason = NULL;