[HBASE-9325] Add functionality to flush and wait and use it in ClientLocalScanner

Author: manukranthk

Summary: Add a functionality in HConnectionManager to perform flushAndWait for flush.

Test Plan: Unit Test

Reviewers: adela, aaiyer, gauravm

Reviewed By: aaiyer

CC: hbase-eng@, liyintang

Differential Revision: https://phabricator.fb.com/D898956

Task ID: 2649976

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1517172 13f79535-47bb-0310-9956-ffa450edef68
[0.89-fb] [ HBASE-7517] Add server name to PFFE Exceptions

Author: aaiyer

Summary: add server name to make debugging easier

Test Plan: eyeball; mvn tests

Reviewers: rshroff, liyintang, mbm

Reviewed By: rshroff

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D914679

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1517173 13f79535-47bb-0310-9956-ffa450edef68