YARN-742. Log aggregation causes a lot of redundant setPermission calls. Contributed by Jason Lowe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1489596 13f79535-47bb-0310-9956-ffa450edef68
YARN-756. Remnants from moving Preemption* records to yarn.api where they really belong. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1489614 13f79535-47bb-0310-9956-ffa450edef68
HDFS-4840. ReplicationMonitor gets NPE during shutdown. Contributed by Kihwal Lee.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1489634 13f79535-47bb-0310-9956-ffa450edef68
YARN-753. Added individual factory methods for all api protocol records and converted the records to be abstract classes. Contributed by Jian He.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1489644 13f79535-47bb-0310-9956-ffa450edef68