AMBARI-1829. HDFS Mirroring: Display Status and handle maintenance operations like Stop, Suspend, Activate etc. (Arun Kandregula via srimanth)

git-svn-id: https://svn.apache.org/repos/asf/incubator/ambari/trunk@1466218 13f79535-47bb-0310-9956-ffa450edef68