Document how to change Bookkeeper Zk root config
### Motivation
Using ```zkServers=zk1:2181/myroot``` current is resulting in Bookie start failure. This PR documents the correct way to configure zookeeper root for Bookkeeper when using Pulsar.
### Modifications
Adding doc line to
@@ -232,6 +232,8 @@ zkServers=zk1.example.com:2181,zk2.example.com:2181,zk3.example.com:2181
ledgerManagerType=hierarchical
```
+To change the zookeeper root path used by Bookkeeper, use zkLedgersRootPath=/MY-PREFIX/ledgers instead of zkServers=localhost:2181/MY-PREFIX
+
> Consult the official [BookKeeper docs](http://bookkeeper.apache.org) for more information about BookKeeper.
## BookKeeper persistence policies
