HADOOP-10479. Merge r1604292 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1604293 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6222. Remove background token renewer from webhdfs. Contributed by Rushabh Shah and Daryn Sharp.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1604301 13f79535-47bb-0310-9956-ffa450edef68