YARN-547. Fixed race conditions in public and private resource localization which used to cause duplicate downloads. Contributed by Omkar Vinit Joshi.
svn merge --ignore-ancestry -c 1470076 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1470078 13f79535-47bb-0310-9956-ffa450edef68