HBASE-8969 Backport HBASE-8535+HBASE-8586 TestHCM#testDeleteForZKConnLeak enhancement to 0.94

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1504215 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8971: Bump 0.94 version to 0.94.10-SNAPSHOT

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.94@1504233 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/0.94' into 0.94-gd
Merge remote branch 'origin/0.94-gd' into fb-HBASE-8553-0.94-gd