YARN-2704. Changed ResourceManager to optionally obtain tokens itself for the sake of localization and log-aggregation for long-running services. Contributed by Jian He.

(cherry picked from commit a16d022ca4313a41425c8e97841c841a2d6f2f54)
HDFS-7128. Decommission slows way down when it gets towards the end. Contributed by Ming Ma.

(cherry picked from commit 80cb472620f0a7889e311ca32212a42b95c6794e)
(cherry picked from commit 7e949744b14e540cc2824eae8e01a3d99714d662)

Conflicts:
	hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
	hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java
YARN-2502. Changed DistributedShell to support node labels. Contributed by Wangda Tan
(cherry picked from commit f6b963fdfc517429149165e4bb6fb947be6e3c99)