public MiniZooKeeperCluster startMiniZKCluster() throws Exception {
    return startMiniZKCluster(1);
  }
Call this if you only want a zk cluster.
@see #shutdownMiniZKCluster()
@return zk cluster started.
hbase-testing-util/src/main/java/org/apache/hadoop/hbase/HBaseZKTestingUtility.java