HBASE-9485 TableOutputCommitter should implement recovery if we don't want jobs to start from 0 on RM restart



git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1547917 13f79535-47bb-0310-9956-ffa450edef68
HBASE-10064. AggregateClient.validateParameters can throw NPE (cuijianwei)

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1548416 13f79535-47bb-0310-9956-ffa450edef68