svn merge -c 1435386 FIXES: MAPREDUCE-4458. Warn if java.library.path is used for AM or Task (Robert Parker via jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1435394 13f79535-47bb-0310-9956-ffa450edef68