merge YARN-737 from branch-2. Throw some specific exceptions directly instead of wrapping them in YarnException. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1491899 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1491914 FIXES: MAPREDUCE-5315.  DistCp reports success even on failure. (mithun and jlowe via daryn)


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1491919 13f79535-47bb-0310-9956-ffa450edef68