Merget r1612449 from trunk: YARN-2013. The diagnostics is always the ExitCodeException stack when the container crashes. (Contributed by Tsuyoshi OZAWA)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1612450 13f79535-47bb-0310-9956-ffa450edef68