Instead of failing when neither PAM_TTY nor PAM_RHOST are available, call
login_access() with "**unknown**" as the second argument.  This will allow
"ALL" rules to match.

Reported by:	Tim Daneliuk <tundra@tundraware.com>
Tested by:	dim@
PR:		83099 193927
MFC after:	3 days
Merge remote-tracking branch 'freebsd/master' into hardened/current/segvguard