use cache lookup for username skin types

fixes steve-model renders for usernames on first request after uuid request was made before

lib/helpers.js

@@ -25,6 +25,8 @@ function store_skin(rid, userId, profile, cache_details, callback) {
     if (!err && userId.length > 16) {
       // updating username with model info from uuid details
       cache.set_slim(rid, profile.name, slim);
+    } else {
+      slim = cache_details ? cache_details.slim : undefined;
     }
 
     if (!err && url) {