HBASE-16572 Sync method in RecoverableZooKeeper failed to pass callback function in (Allan Yang)

hbase-client/src/main/java/org/apache/hadoop/hbase/zookeeper/RecoverableZooKeeper.java

@@ -763,7 +763,7 @@ public class RecoverableZooKeeper {
   }
 
   public void sync(String path, AsyncCallback.VoidCallback cb, Object ctx) throws KeeperException {
-    checkZk().sync(path, null, null);
+    checkZk().sync(path, cb, null);
   }
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -199,6 +199,7 @@ import com.google.protobuf.Service;
 public class HMaster extends HRegionServer implements MasterServices, Server {
   private static final Log LOG = LogFactory.getLog(HMaster.class.getName());
 
+
   /**
    * Protection against zombie master. Started once Master accepts active responsibility and
    * starts taking over responsibilities. Allows a finite time window before giving up ownership.