Remove NameNode URI from ZK splitlogs

When moving to HDFS HA or removing HA we end up changing the NN namespace. This can cause the HMaster not to start up fully due to trying to split phantom HLogs pointing to the wrong FS - java.lang.IllegalArgumentException: Wrong FS: error messages. The HLogs in question might not even be on HDFS anymore. You have to go in a manually clear out the ZK splitlogs directory to get HBase to properly boot up.