Merge pull request #4172 from HeroicEric/cleanup-service-shim

[CLEANUP] Remove shim for Ember.Service

Author: bmac

addon/-private/system/store.js

@@ -118,10 +118,7 @@ var Promise = Ember.RSVP.Promise;
 var copy = Ember.copy;
 var Store;
 
-var Service = Ember.Service;
-if (!Service) {
-  Service = Ember.Object;
-}
+const { Service } = Ember;
 
 // Implementors Note:
 //