Refs #9165: Per Tenant Celery QoS

There was a need for reassignment while managing dict using multiprocessing manager that was used earlier for synchronization of lists among different worker processes (if they started consuming from same queues). Since we are now back to normal dict (consuming distinct queues per worker) so have removed re-assignment in f448c6100119b03f0195eaa891717df5a57aa60d. Thanks