[Master] Rack expansion (expanding existing regions to one new rack)

Author: adela

Summary: We are moving only a number of tertiaries from the old racks to a new rack

Test Plan: run the tool and check

Reviewers: liyintang

Reviewed By: liyintang

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D626932

Task ID: 735404

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1471579 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-8114][89-fb] Interrupt the RS RPC call when the client connection has been closed

Author: adela

Summary:
my changes were overwritten by a rebase that I did and I
figured out that the logic is not in trunk, fixing it

Test Plan:
mr unit tests finished successfully. Since this is hard to test with a unit test I was testing with the following scenario:
- Instead of testing whether the client has closed the connection I put a very small timeout ~100ms.
- I start a scan over a table. - The scan times out because 100ms expired.

Reviewers: manukranthk, liyintang

Reviewed By: manukranthk

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D783731

Task ID: 2044405

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1471580 13f79535-47bb-0310-9956-ffa450edef68