YARN-903. Changed ContainerManager to suppress unnecessary warnings when stopping already stopped containers. Contributed by Omkar Vinit Joshi.
svn merge --ignore-ancestry -c 1509560 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1509562 13f79535-47bb-0310-9956-ffa450edef68