Milter modifies all mail

[Dan O'Brien]

OK... I'm pretty sure I know *why* (now), but this might warrant a patch. 
I'm setting up a new SpamAssassin relay.

I have (well, *HAD*) the following option in SpamAssassin 3.0.2's 
local.cf:

        add_header all Flag _YESNOCAPS_

My old server had the default, which is

        add_header spam Flag _YESNOCAPS_

The milter seems to act on the presence of the X-Spam-Flag header, rather 
than the contents of the header (YES = spam, NO = ham).  As such, *all* of 
the mail was getting bucketed.  No blood, no foul -- that's what testing 
is for -- but I was a little mystified at first.