[Mimedefang] tempfail with multiple virus scanners

[Juergen Georgi]

Hi,

currently message_contains_virus() and entity_contains_virus()
return the "tempfail" action, if one of the installed virus scanners 
is unavailable, even if there are multiple virus scanners in use.

Is it possible to gracefully skip a failing virus scanner, if at 
least one other virus scanner is working? I'd like to use
two comparable scan daemons for complement and failover reasons.

Thanks,

-Juergen Georgi