YARN-649. Added a new NM web-service to serve container logs in plain text over HTTP. Contributed by Sandy Ryza.
svn merge --ignore-ancestry -c 1519326 ../../trunk/


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1519327 13f79535-47bb-0310-9956-ffa450edef68