HDFS-6041. Downgrade/Finalize should rename the rollback image instead of purging it. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-5535@1573851 13f79535-47bb-0310-9956-ffa450edef68
5 files changed