do not check the jobid if check-locks is False

Because it relies on the lock server which is presumably not available
since check-locks was set to False. It matters when using teuthology
on a minimal installation.

http://tracker.ceph.com/issues/5946 fixes #5946

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #27 from dachary/wip-5946

do not check the jobid if check-locks is False