Change to mailing list settings

[Ken Bloom]

Due to an increasing amount of spam headed towards the vcs-home mailing
list, I have changed the mailing list settings to automatically reject
emails from people who are not subscribed to the list. (Rather than the
old default which was to send them to a moderator for approval.)

I don't think I've ever had a legitimate message that required
moderation, so I don't think any of you will notice this change, but if
you do let me know.

--Ken Bloom