In previous releases, /etc/localtime was a symlink into
/usr/share/zoneinfo.

I've made changes to initscripts & timeconfig that make
/etc/localtime be a copy of the relevant file under
/usr/share, with the location being stored in
/etc/sysconfig/clock
(for lack of anyplace better).

Rationale:
- it allows us to set the clock as soon as the initscripts
start
- it allows machines with nfs-mounted /usr to set the clock
correctly
(this has been broken for quite a while, AFAICT)