more spec-like array sorting 👓

https://github.com/GoogleCloudPlatform/gcloud-node/pull/316\#discussion_r21193388

Author: stephenplusplus

lib/datastore/transaction.js

@@ -182,7 +182,7 @@ Transaction.prototype.commit = function(callback) {
 
     // Group entities together by action (delete or save).
     .sort(function (a, b) {
-      return a.method > b.method;
+      return a.method > b.method ? 1 : a.method < b.method ? -1 : 0;
     })
 
     // Group arguments together so that we only make one call to each method.