Move HDFS-4949 subtasks in CHANGES.txt to a new section under 2.4.0 release.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560528 13f79535-47bb-0310-9956-ffa450edef68
YARN-1607. TestRM relies on the scheduler assigning multiple containers in a single node update (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560533 13f79535-47bb-0310-9956-ffa450edef68
YARN-1623. Include queue name in RegisterApplicationMasterResponse (Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560545 13f79535-47bb-0310-9956-ffa450edef68
HDFS-5806. Balancer should set soTimeout to avoid indefinite hangs. Contributed by Nathan Roberts.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1560548 13f79535-47bb-0310-9956-ffa450edef68