zookeeper - autopurge interval - active every 3/hrs

The current default value is to not purge. Here we set a default value to
purge the data.

On production we experienced an issue where we filled the data disk due to
the fact the db never purged.

https://zookeeper.apache.org/doc/r3.4.5/zookeeperAdmin.html#sc_advancedConfiguration

Change-Id: Idc93a11a4bfe403a3d76d87f2a18e7e0bd90ca56

controllers/static/zookeeper/run.sh

@@ -20,7 +20,7 @@ ZK_MAX_CLIENT_CNXNS=${ZK_MAX_CLIENT_CNXNS:-60}
 ZK_MIN_SESSION_TIMEOUT=${ZK_MIN_SESSION_TIMEOUT:- $((ZK_TICK_TIME*2))}
 ZK_MAX_SESSION_TIMEOUT=${ZK_MAX_SESSION_TIMEOUT:- $((ZK_TICK_TIME*20))}
 ZK_SNAP_RETAIN_COUNT=${ZK_SNAP_RETAIN_COUNT:-3}
-ZK_PURGE_INTERVAL=${ZK_PURGE_INTERVAL:-0}
+ZK_PURGE_INTERVAL=${ZK_PURGE_INTERVAL:-3}
 JMXPORT=1099
 JMXSSL=false
 JMXAUTH=false