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)

Add a namedb/master directory for the zone files I'm about to add,
and switch to the more "normal" way of installing files for the
namedb directory so that we can pick up the new subdir.