[Mailman] python.org: removing old Mailman lists

[A.M. Kuchling]

The following Mailman lists are old and can be removed, I think.

	psf-prc
	pycon2005-attendees
	soc2006-mentors

I've cc'ed James Tauber because of the soc2006-mentors list;
he's the SoC coordinator, and maybe he wants to keep the mentor list
around.

--amk