Stop classifying msgs for unknown areas as security violations

When Secure EchoMail is enabled and a Bad Echo Area (*) is defined in the
area file (areas.bbs), but the packet source address is *not* listed as a
link to the Bad Echo Area (tag: *) in areas.bbs, any messages for unknown
areas in such a packet would cause the pkt to be considered a bad packet
with a security violation. Instead, the message should just be skipped.