Moving recent bug-fixes to hadoop-2.2.1.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1530129 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5316. Merging change 1530150 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1530153 13f79535-47bb-0310-9956-ffa450edef68