Fix deadlock observed in T13390459 Summary: Fix deadlock in ping timer callback. Test Plan: run, mount volume. Reviewers: rwareing Reviewed By: rwareing Differential Revision: https://phabricator.intern.facebook.com/D3744945 Signature: t1:3744945:1474061471:3e3d1a5cefc541d26973535887c1f08c017fc049 Change-Id: Iaf94eb4c3acaa8b3ceeeb6a273db4109eea29a7c Signed-off-by: Kevin Vigor <kvigor> Reviewed-on: http://review.gluster.org/16168 Smoke: Gluster Build System <jenkins.org> NetBSD-regression: NetBSD Build System <jenkins.org> Reviewed-by: Shreyas Siravara <sshreyas> CentOS-regression: Gluster Build System <jenkins.org>