openantivirus support

[Devin Reade]

For people's general info, I've patched MailScanner to support
the www.openantivirus.org ScannerDaemon back end.  Support will
not be official in MailScanner until Julian's "big rewrite",
but I will be making an interim patch + instructions available.

I'm a bit delayed at the moment due to having to deal with
an unrelated server hardware failure, but I figured I'd mention
it in case anyone else was thinking about adding openantivirus
support.

--
         Devin Reade         <gdr at gno.org>