Deploy Script Improvement

[sivkovic]

Modify the deploy script so celery can gracefully shutdown.
We need a better way to restart celery. What's been happening is that the Worker will not shutdown gracefully and leave a PID so that it can no longer be started. The beat will restart and continue to queue jobs. When the worker is finally restarted, all of the beat jobs will run at once. This means that check_status will run N times, milliseconds apart, same with submit_pending_jobs, etc.