Spam headers @fp.o addresses

[Mike McGrath]

I've started adding spam headers to all @fp.o emails.  Please keep your
eyes and ears out for any strangeness.  We'll likely have to further
configure things.  I've also been considering changing the standard spam
headers to fedora specific headers so people understand where they are
coming from and can use them, in conjunction with their local spam
scanners.

I'm really not sure what happens to our spam headers if another
spamassassin server scans them, I'd assume ours would just vanish.

	-Mike