Keep old shouldBackgroundReloadRecord behaviour ready for 2.0 upgrade

no issue
- adds `shouldBackgroundReloadRecord` override so that we keep the current behaviour (never background reload unless instigated manually) when we upgrade to Ember Data 2.0 which will always background-reload by default

ghost/admin/app/adapters/application.js

@@ -1,3 +1,9 @@
 import EmbeddedRelationAdapter from 'ghost/adapters/embedded-relation-adapter';
 
-export default EmbeddedRelationAdapter.extend();
+export default EmbeddedRelationAdapter.extend({
+
+    shouldBackgroundReloadRecord: function () {
+        return false;
+    }
+
+ });

ghost/admin/app/adapters/base.js

@@ -5,6 +5,10 @@ export default DS.RESTAdapter.extend({
     host: window.location.origin,
     namespace: ghostPaths().apiRoot.slice(1),
 
+    shouldBackgroundReloadRecord: function () {
+        return false;
+    },
+
     query: function (store, type, query) {
         var id;