HBASE-8586 Revisit of hbase-8483, "HConnectionManager can leak ZooKeeper connections when using deleteStaleConnection"

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1484926 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8581 rpc refactor dropped passing the operation timeout through to the rpcclient

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1484939 13f79535-47bb-0310-9956-ffa450edef68
HBASE-8581 rpc refactor dropped passing the operation timeout through to the rpcclient

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.95@1484941 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/0.95' into 0.95-gd