@aronasorman thanks for the comment.  For me, this is definitely not the right solution.  The best one I can think of:
* Do `call_command_async('update', mechanism, old_server_pid=os.getpid(), in_proc=True)`  Eliminate `in_proc` from the argument list for `call_command_async`, and pull it off of the `kwargs` list (you'll have to `del`).

This construct is used elsewhere in the code to deal with similar situations.