Updated CHANGES.txt for HDFS-6581 merge into branch-2.6.
HDFS-7204. balancer doesn't run as a daemon (aw)
YARN-2709. Made timeline client getDelegationToken API retry if ConnectException happens. Contributed by Li Lu.
YARN-2715. Fixed ResourceManager to respect common configurations for proxy users/groups beyond just the YARN level config. Contributed by Zhijie Shen.
YARN-2721. Suppress NodeExist exception thrown by ZKRMStateStore when it retries creating znode. Contributed by Jian He.
YARN-2692 ktutil test hanging on some machines/ktutil versions (stevel)
MAPREDUCE-6126. Fixed Rumen JobBuilder to ignore NormalizedResourceEvent. Contributed by Junping Du
HDFS-7228. Fix TestDNFencing.testQueueingWithAppend. Contributed by Yongjun Zhang.
Updated CHANGES.txt to move MAPREDUCE-6126 to 2.6
Merge branch 'apache-trunk' into HDFS-6934
HDFS-6934: Add assertions about state of meta files.