* CHANGES: Merge 1.6.21 entries from trunk (r1462300, r1462302, r1462321, r1462334)

Some conflicts were resolved where 1.7.9 entries were made in the same revision.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.6.x@1462336 13f79535-47bb-0310-9956-ffa450edef68