HBASE-11119 Update ExportSnapShot to optionally not use a tmp file on external file system (Ted Malaska)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1593337 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8332 Add truncate as HMaster method

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1593439 13f79535-47bb-0310-9956-ffa450edef68