Merged revision(s) 1603356 from hadoop/common/trunk:
HADOOP-10590. ServiceAuthorizationManager is not threadsafe. (Contributed by Benoy Antony)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1603357 13f79535-47bb-0310-9956-ffa450edef68