HBASE-7415 Add task information to snapshot operation (Jesse Yates)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1464928 13f79535-47bb-0310-9956-ffa450edef68
HBASE-7615 Add metrics for snapshots

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1464931 13f79535-47bb-0310-9956-ffa450edef68