Merge branch 'stable-2.9'

* stable-2.9:
  Executing CherryPick.writeCherryPickCommit() in a transaction.
  Bump API version to 2.8.6
  Release notes for Gerrit 2.8.6
  Add missing 'link:' in 2.8.5 release notes
  ChangeMergeQueue: Fix race condition

Conflicts:
	VERSION

Change-Id: I736038ec00d7e9656de0d5b9043498a479cdbd01