wait for subprocess to remove a file before trying to stop it
wait for subprocess to remove a file before trying to stop it

The previous STOP_DELAY was used because we had to wait for Python
to finish starting.  Instead, we should wait for the interpreter to
perform some action before interrupting, terminating or killing the
process.

guidow/pyfarm-agent,guidow/pyfarm-agent,pyfarm/pyfarm-agent,pyfarm/pyfarm-agent,pyfarm/pyfarm-agent,guidow/pyfarm-agent