Spam filter rules tweaked

[Russ Allbery]

Spam sent directly to the list address was getting thorugh, so I've
tweaked the spam filter rules to not allow postings from non-members
except for a bunch of Debian infrastructure and anything that comes from
the BTS.  Hopefully this won't cause too much of a problem and I got all
the rules right.  I'll keep a close watch on the moderation queue for a
while and deal with anything that gets stuck.  Yell at me if anything
breaks.

-- 
Russ Allbery (rra at debian.org)               <http://www.eyrie.org/~eagle/>