YARN-7. Support CPU resource for DistributedShell. (Junping Du via llu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1531222 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5276. Remove volatile from LightWeightHashSet. (Junping Du via llu)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1531225 13f79535-47bb-0310-9956-ffa450edef68
Move HDFS-5276 to 2.3.0 in CHANGES.txt

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1531228 13f79535-47bb-0310-9956-ffa450edef68