HDFS-6475. WebHdfs clients fail without retry because incorrect handling of StandbyException. Contributed by Yongjun Zhang.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1605218 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10747. Merging change r1605219 from trunk to branch-2.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1605225 13f79535-47bb-0310-9956-ffa450edef68