watcher:  fix bad comparison to None

When a process exits with status == 0 and is reaped by the arbiter,
watcher.reap_process incorrectly tries to reap the process itself due to
testing status as a boolean and not testing if the status is None.
watcher:  notify process exit code when reaping

Add the exit code of the reaped process to the notify event.
process:  remove debuglog from returncode
Merge pull request #652 from jsbronder/reap_with_exit_status

Reap with exit status