Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

tabify

MFC after: 3 weeks

Change the pam_ssh examples: if you use it, you probably want want_agent.

MFC after: 3 weeks

Add a system policy, and have the login and su policies include it rather
than duplicate it. This requires OpenPAM Dianthus, which was committed two
weeks ago; installing these files on a system running a world older than
June 1st, 2003 will cause login(1) and su(1) to fail.