[HBASE-9219] Fix TestMergeMeta and TestMergeTable

Author: manukranthk

Summary: This diff fixes TestMergeMeta and TestMergeTable. There was a Zookeeper cluster setup embedded inside the HBaseClusterSetup step. Seperating both the steps.

Test Plan: Verify the unit tests passing.

Reviewers: liyintang, adela, rshroff

Reviewed By: rshroff

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D925600

Task ID: 2728818

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1514421 13f79535-47bb-0310-9956-ffa450edef68