AMBARI-5298. Mirroring: Start sorting works incorrect. (akovalenko)

ambari-web/app/controllers/main/mirroring_controller.js

@@ -181,8 +181,8 @@ App.MainMirroringController = Em.ArrayController.extend({
             id: instance.instance + '_' + opts.dataset,
             name: instance.instance,
             status: instance.status,
-            endTime: new Date(instance.endTime).getTime(),
-            startTime: new Date(instance.startTime).getTime()
+            endTime: new Date(instance.endTime).getTime() || 0,
+            startTime: new Date(instance.startTime).getTime() || 0
           });
         }
       }, this);