Pidgin security mailing list small changes

[Mark Doliner]

The security mailing list previously had a max of 40KB per email.
Messages larger than that got put into the admin queue.  I bumped up
this limit to 200KB.

The "owner" of the list was also set to root at pidgin.im.  I don't know
where that email goes, but it isn't me.  No one was tending to the
pending messages in the queue.  I fixed this by setting myself as the
owner of the list and going through the queue and deleting spam and
allowing non-spam (hence the flood of emails).

--Mark