Fix tiny memory leak in $.cache.

4chan_x.user.js

@@ -388,6 +388,7 @@
             cb = _ref[_i];
             cb.call(this);
           }
+          return delete this.callbacks;
         },
         onabort: function() {
           return delete reqs[url];

script.coffee

@@ -306,7 +306,7 @@ $.extend $,
     req = $.ajax url,
       onload:  ->
         cb.call @ for cb in @callbacks
-        return
+        delete @callbacks
       onabort: -> delete reqs[url]
       onerror: -> delete reqs[url]
     req.callbacks = [cb]