Update CHANGES-HDFS-4685.txt for several issues that have been converted to Hadoop Common sub-tasks of HADOOP-10184.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-4685@1553602 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'HDFS-4685' into HDFS-5673