YARN-2081. Fixed TestDistributedShell failure after YARN-1962. Contributed by Zhiguo Hong.
svn merge --ignore-ancestry -c 1596724 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.4@1596726 13f79535-47bb-0310-9956-ffa450edef68