HDFS-6276. Remove unnecessary conditions and null check. Contributed by Suresh Srinivas

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1589586 13f79535-47bb-0310-9956-ffa450edef68
MAPREDUCE-5846. Rumen doesn't understand JobQueueChangedEvent (Nathan Roberts via raviprak)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1589595 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6278. Create HTML5-based UI for SNN. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1589613 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6279. Create new index page for JN / DN. Contributed by Haohui Mai.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1589618 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5693. Few NN metrics data points were collected via JMX when NN is under heavy load. Contributed by Ming Ma.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1589620 13f79535-47bb-0310-9956-ffa450edef68