[HBASE-2376] Remove injection from compaction codepath

Author: pritam

Test Plan: Run the unit test.

Reviewers: kannan, liyintang

Reviewed By: kannan

CC: hbase-eng@

Differential Revision: https://phabricator.fb.com/D669948

Task ID: 1944096

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1428557 13f79535-47bb-0310-9956-ffa450edef68