consistent with what FreeBSD uses /etc/defaults for, and since SVR4
uses /etc/default for another purpose.
as discussed on tech-userlevel, and no objections were made.
and source the latter in the former. this makes it easier for a sysadmin to
upgrade the default files without affecting local config, and retains the
semantics that the /etc/foo.conf files are the actual files that are edited
(as opposed to /etc/foo.local.conf or /etc/foo.conf.local or whatever, which
isn't as intuitive).
