[master]Let HMaster not close DFS client when there is transient failure

Author: fan

Summary: Currently when DFS client has problem, HMaster will close it but still loops on checking its availability. So when name node comes back, HMaster does not recover.

Test Plan: Push new jar to master of a shadow cluster, then shut down name node for a couple minutes. When name node is brought back, HMaster should recover soon.

Reviewers: aaiyer

Reviewed By: aaiyer

CC: hbase-eng@, manukranthk

Differential Revision: https://phabricator.fb.com/D956599

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1520653 13f79535-47bb-0310-9956-ffa450edef68