[HBASE-11035] Online configuration change for loaded coprocessors

Author: adela

Summary: trying out if online config works when new coprocessors are added, so far so good

Test Plan: added a unit test

Reviewers: daviddeng, elliott, gauravm

Reviewed By: daviddeng

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D1278985

Task ID: 4146171

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1588689 13f79535-47bb-0310-9956-ffa450edef68
[HBASE-10343] Record the sequence id change when region opens on region server.

Author: everyoung

Summary:
- Add historian to ROOT table.
- Add immutable HRegionSeqidTransition class and TestHRegionSeqidTransition to
  test ser/deser and region reopen.
- Add serverInfo and RegionInfo as Jiqing suggested
- Fix TestDistributedLogSplitting, TestMutationWriteToWAL.
- Add config to enable/disable ROOT_DESCRIPTOR changes.

Test Plan: all tests and a new unit test

Reviewers: aaiyer, liyintang, rshroff, jiqingt

Reviewed By: aaiyer

CC: hbase-dev@, andrewcox, fan

Differential Revision: https://phabricator.fb.com/D1232574

Task ID: 3946433

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1588690 13f79535-47bb-0310-9956-ffa450edef68