[HBASE-6371] [0.89-fb] BugFix: concurrency problem, was locking on an Integer created by auto-boxing ; now uses a lock-free integer (AtomicLong) to avoid locking and concurrency issues.

Author: jmarg

Summary: BugFix: concurrency problem, was locking on an Integer created by auto-boxing ; now uses a lock-free integer (AtomicLong) to avoid locking and concurrency issues.

Test Plan:
Run the test suite of HBase using maven:
  $ mvn test

Reviewers: aaiyer, manukranthk

Reviewed By: aaiyer

CC: san, rongrong

Differential Revision: https://phabricator.fb.com/D1014395

Task ID: 3008730

git-svn-id: https://svn.apache.org/repos/asf/hbase/branches/0.89-fb@1533191 13f79535-47bb-0310-9956-ffa450edef68