merge MAPREDUCE-5286 from trunk. Change MapReduce to use ContainerTokenIdentifier instead of the entire Container in the startContainer call - YARN-684. Contributed by Vinod Kumar Vavilapalli.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1488088 13f79535-47bb-0310-9956-ffa450edef68