HBASE-8753 Provide new delete flag which can delete all cells under a column-family which have designated timestamp (Honghua)



git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1500779 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/0.95' into 0.95-gd