svn merge -c 1481075 Merging from trunk to branch-2 to fix HADOOP-9549.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1481077 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1481084. Merging from trunk to branch-2 to fix HDFS-4799.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1481086 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4751. TestLeaseRenewer#testThreadName flakes. Contributed by Andrew Wang.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1481166 13f79535-47bb-0310-9956-ffa450edef68