Don't allocate space for a %u and then stick a %d in it.

Tripped by:	anordby



git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@3183 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishd/cache_vrt.c

@@ -480,7 +480,7 @@ VRT_r_req_xid(struct sess *sp)
 
 	size = snprintf(NULL, 0, "%u", sp->xid) + 1;
 	AN(p = WS_Alloc(sp->http->ws, size));
-	assert(snprintf(p, size, "%d", sp->xid) < size);
+	assert(snprintf(p, size, "%u", sp->xid) < size);
 	return (p);
 }