HDFS-6340: Merging r1593436 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1593437 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1593470 merging from trunk to branch-2 to fix:HDFS-6329. WebHdfs does not work if HA is enabled on NN but logical URI is not configured. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1593471 13f79535-47bb-0310-9956-ffa450edef68
Fix CHANGES.txt

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1593474 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1593475 merging from trunk to branch-2 to fix:HDFS-6313. WebHdfs may use the wrong NN when configured for multiple HA NNs. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1593476 13f79535-47bb-0310-9956-ffa450edef68