When split doing offlineParentInMeta encounters error, it'll cause data loss

Follow below steps to replay the problem:
1. change the SplitTransaction.java as below,just like mock the timeout error.

      if (!testing) {
        MetaEditor.offlineParentInMeta(server.getCatalogTracker(),
           this.parent.getRegionInfo(), a.getRegionInfo(), b.getRegionInfo());
        throw new IOException("some unexpected error in split");
      }
   

2. update the regionserver code,restart;
3. create a table & put some data to the table;
4. split the table;
5. kill the regionserver hosted the table;
6. wait some time after master ServerShutdownHandler.process execute,then scan the table,u'll find the data wrote before lost.

We can fix the bug just use the patch.