MAPREDUCE-5911. Terasort TeraOutputFormat does not check for output directory existance. Contributed by Bruno P. Kinoshita.
Revert "MAPREDUCE-5911. Terasort TeraOutputFormat does not check for output directory existance. Contributed by Bruno P. Kinoshita."

This reverts commit 7bbda6ef92e9bf4a28e67b8736067b38defab51e.
HADOOP-11194. Ignore .keep files (kasha)
HDFS-7184. Allow data migration tool to run as a daemon. (Benoy Antony)
YARN-2673. Made timeline client put APIs retry if ConnectException happens. Contributed by Li Lu.
YARN-2582. Fixed Log CLI and Web UI for showing aggregated logs of LRS. Contributed Xuan Gong.
HDFS-7266. HDFS Peercache enabled check should not lock on object (awang via cmccabe)
HDFS-7154. Fix returning value of starting reconfiguration task (Lei Xu via Colin P. McCabe)
YARN-2701. Potential race condition in startLocalizer when using LinuxContainerExecutor. Contributed by Xuan Gong
Missing file for YARN-2701
Missing file for YARN-1879
YARN-2717. Avoided duplicate logging when container logs are not found. Contributed by Xuan Gong.
HDFS-7259. Unresponseive NFS mount point due to deferred COMMIT response. Contributed by Brandon Li
YARN-90. NodeManager should identify failed disks becoming good again. Contributed by Varun Vasudev
HDFS-7215.Add JvmPauseMonitor to NFS gateway. Contributed by Brandon Li
YARN-2720. Windows: Wildcard classpath variables not expanded against resources contained in archives. Contributed by Craig Welch.
HDFS-7221. TestDNFencingWithReplication fails consistently. Contributed by Charles Lamb.
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.