Return true in onStartJob.

Returning true indicates that there is ongoing work.

Bug: 148754858
Test: None
Change-Id: I31bc4f986803a1462f87779d3f4eb14e10d7f841

apex/blobstore/service/java/com/android/server/blob/BlobStoreIdleJobService.java

@@ -42,7 +42,7 @@ public class BlobStoreIdleJobService extends JobService {
             blobStoreManagerInternal.onIdleMaintenance();
             jobFinished(params, false);
         });
-        return false;
+        return true;
     }
 
     @Override