[dev] chora restricted files patch

[Max Kalika]

Quoting Chuck Hagenbuch <chuck@horde.org>:

> I'd rather see something like this use Perms::, but since that isn't
> quite there yet, this is a good interim measure - and I know people have
> requested something similar. I don't see a reason not to add it.

I thought about it, but there were a few hitches.  I don't know if cvs 
admins will want to set up horde accounts just to restrict certain files. 
Of course it would be useful for group projects or somesuch.  Anyway, this 
is a rather small and self-contained patch.  It will do for now, right? 
I'll commit it in a minute.

---max kalika
--max@lsit.ucsb.edu
-lsit systems administrator