HBASE-12582 Backport HBASE-10881 'Support reverse scan in thrift2' to 0.98 (Ted Yu)
HBASE-12624 Remove rename_snapshot.rb from code as there is no equivalent renameSnapshot api in Admin class (Ashish Singhi)
HBASE-12431 Use of getColumnLatestCell(byte[], int, int, byte[], int, int) is Not Thread Safe (Jingcheng Du)

(cherry picked from commit c45772e76a581838ea89ff303d0ff67ceaa82845)