HBASE-9708 Improve Snapshot Name Error Message (Esteban Gutierrez)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1573962 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10537 Let the ExportSnapshot mapper fail and retry on error

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1574016 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10567 Add overwrite manifest option to ExportSnapshot

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1574017 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10622 Improve log and Exceptions in Export Snapshot

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1574034 13f79535-47bb-0310-9956-ffa450edef68