@Override
    public void start(Path configFilePath) {
        peer.start(configFilePath);
    }
Starts or reconfigures zookeeper cluster.
The QuorumPeer conditionally created here is owned by the Reconfigurer;
when it already has a peer, that peer is used here in case start or shutdown is required.
Guarantees that server is up by writing a node to ZooKeeper successfully before
returning from constructor.

@author hmusum
zookeeper-server/zookeeper-server/src/main/java/com/yahoo/vespa/zookeeper/ReconfigurableVespaZooKeeperServer.java