According to my understanding, both 2 threads are effective for zookeeper mode only.  See the code snippet in constructor.
```
if (mZookeeperMode) {
        ...
        mEditLogProcessor = new EditLogProcessor(mJournal, journalFolder, mMasterInfo);
        Thread logProcessor = new Thread(mEditLogProcessor);
        logProcessor.start();
 }
```
so we need to close both of them in zookeeper mode only, like
```
if (mZookeeperMode) {
      if (mLeaderSelectorClient != null) {
        mLeaderSelectorClient.close();
      }
      if (mEditLogProcessor != null) {
        mEditLogProcessor.stop();
      }
    }
```