prevent ember searching for non-existant custom event dispatchers

ghost/admin/app/initializers/event-dispatcher.js

@@ -0,0 +1,18 @@
+// TODO: remove this file once canDispatchToEventManager is deprecated
+// https://github.com/emberjs/ember.js/issues/14754
+import Ember from 'ember';
+
+const {EventDispatcher} = Ember;
+
+const myEventDispatcher = EventDispatcher.extend({
+    canDispatchToEventManager: false
+});
+
+export function initialize(application) {
+    application.register('event_dispatcher:main', myEventDispatcher);
+}
+
+export default {
+    name: 'event-dispatcher',
+    initialize
+};