Do not mark the empty pushs as failed (#4497)

src/Push/PushQueue.js

@@ -38,7 +38,7 @@ export class PushQueue {
         {limit: 0, count: true});
     }).then(({results, count}) => {
       if (!results || count == 0) {
-        return Promise.reject({error: 'PushController: no results in query'})
+        return pushStatus.complete();
       }
       pushStatus.setRunning(Math.ceil(count / limit));
       let skip = 0;