make RandomMergePolicy log what MP it is wrapping (merge r1514815)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1514818 13f79535-47bb-0310-9956-ffa450edef68
SOLR-5156 Provide a way to move the contents of a file to ZooKeeper with ZkCLI

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1514821 13f79535-47bb-0310-9956-ffa450edef68