No longer need to count the references in webContents

All remote objects are now cached in renderer process, so there is
always only one reference to one remote object for each webContents.

atom/browser/lib/rpc-server.js

@@ -145,7 +145,7 @@ var exceptionToMeta = function(error) {
 var unwrapArgs = function(sender, args) {
   var metaToValue;
   metaToValue = function(meta) {
-    var i, len, member, ref, rendererReleased, returnValue;
+    var i, len, member, ref, returnValue;
     switch (meta.type) {
       case 'value':
         return meta.value;