patches to make bind9 with TKEY/GSS updates easier to configure

[Evan Hunt]

> The last patch is certainly strange I know, but GSSAPI doesn't give us
> many options if we want to be able to do updates against something
> other than the default realm.

Without having reviewed the patch, two comments:

 - should this be a named.conf option instead of an environment variable?
 - can this be used in the tsiggss test, so that the test can run without
   need for any system-wide configuration?

-- 
Evan Hunt -- each at isc.org
Internet Systems Consortium, Inc.