fork child process for processing job.

This patch is to enable forking of child process for processing the
given job. The forking of child process can be enabled or disabled using
the qonos worker config param flag, 'fork_child_process'. By default
fork_child_process is disabled ie., set to 'False'.
This is being used as a signal handler. Are you suggesting creating a new function to act as a signal handler and have it call this function and update this function with a reason?

def new_signal_handler_to_replace_stop_processor(self, signum, frame):
    stop_processor()

def stop_processor(self, reason):
    pass

Something like that? If so, that would be fine. I don't think stop_processor is being used outside a signal handling context, so I don't know if it should be changed now or refactored when needed. Making the update would be easy enough now though. Let me know if my understanding is correct. Thanks!