Don't consider TCP connections beyond LISTEN state
(i.e. with the foreign address being not wildcard) when checking
for possible port theft since such connections cannot be stolen.

The port theft check is FreeBSD-specific and isn't in the KAME tree.

PR: bin/65928 (in the audit trail)
Reviewed by: -net, -hackers (silence)
Tested by: Nick Leuta <skynick at mail.sc.ru>
MFC after: 1 month