Preperation for ZooKeeper failover

- Add template for specifying backup ZooKeeper connections.
 - ONOS -> ZooKeeper
 - RAMCloud -> ZooKeeper
- Fix RCClient to properly handle multiple ZooKeeper configuration.

Change-Id: I91ea078feca1b84fdf76a74624f8f5e0712214e8
diff --git a/conf/onos.properties b/conf/onos.properties
index 0235dc0..c8509cf 100644
--- a/conf/onos.properties
+++ b/conf/onos.properties
@@ -13,3 +13,5 @@
 net.floodlightcontroller.forwarding.Forwarding.hardtimeout = 0
 # NOTE: Do NOT modify or remove the line below. This value will be overwritten by onos.sh script.
 net.onrc.onos.core.datagrid.HazelcastDatagrid.datagridConfig = 
+# Uncomment and list all the ZooKeeper instances after localhost on multi-instance deployment.
+#net.onrc.onos.core.registry.ZookeeperRegistry.connectionString = localhost:2181,otherhost:2181