pf: do not pass af to PFLOG_PACKET

Do not pass AF specific information to pf_test_rule() and PFLOG_PACKET()
because either the info is already available in struct pd or easy
to figure out. Makes pf_test() and pf_test6() even more similar
(with the target to remove one of them in the near future).
OK henning@

Reviewed by: zlei
Obtained from: OpenBSD, claudio <claudio@openbsd.org>, 5480721ed1
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D46596