Reimplement getMasterInfoPort for Admin

  public int getMasterInfoPort() throws IOException {
    // TODO: Fix!  Reaching into internal implementation!!!!
    ConnectionImplementation connection = (ConnectionImplementation)this.connection;
    ZooKeeperKeepAliveConnection zkw = connection.getKeepAliveZooKeeperWatcher();
    try {
      return MasterAddressTracker.getMasterInfoPort(zkw);
    } catch (KeeperException e) {
      throw new IOException("Failed to get master info port from MasterAddressTracker", e);
    }
  }