YARN-649. Added a new NM web-service to serve container logs in plain text over HTTP. Contributed by Sandy Ryza.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1519326 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-HADOOP-9063-trunk-gd