retry runner doesn't shut down on `mailman stop`
Whenever I shut mailman down, I am left with one runner that doesn't exit. It looks like it's always the retry runner.
This also happens if I just start and immediately shut mailman down (using a fresh database).
According to the logs the runner receives SIGTERM but doesn't do anything with it.
The logs include retry runner caught SIGTERM. Stopping.
They don't include the message that it actually exits.