Fix regression in flock usage
Fix regression in flock usage

Bug report: http://tracker.ceph.com/issues/14336
Regression caused in: https://github.com/ceph/teuthology/pull/764

Signed-off-by: Zack Cerza <d7cdf09fc0f0426e98c9978ee42da5d61fa54986@redhat.com>

dmick/teuthology,dmick/teuthology,SUSE/teuthology,SUSE/teuthology,dmick/teuthology,ceph/teuthology,SUSE/teuthology,ktdreyer/teuthology,ktdreyer/teuthology,ceph/teuthology