YARN-1910. Fixed a race condition in TestAMRMTokens that causes the test to fail more often on Windows. Contributed by Xuan Gong.
svn merge --ignore-ancestry -c 1586192 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.4@1586194 13f79535-47bb-0310-9956-ffa450edef68