Confirming decision not to care about cross-realm armor for 1.8

[Sam Hartman]

As you see from my message to ietf-krb-wg, cross-realm armor tickets
for FAST negotiation are a bit tricky.  My proposal is that we ignore
them for 1.8 and that we require FAST if the KDC we AS exchange with
to obtain the armor ticket supports FAST.

This isn't quite right for AD deployments, but I think we can evolve
our support as the standard evolves in the future.

--Sam