[krbdev.mit.edu #7885] International domain names

[nalin@redhat.com via RT]

We don't seem to have any specific support for international domain
names when specifying KDC names.

MS-KKDCP support, being based on HTTPS, will probably require that we
also start checking the name recorded in the server's certificate.
RFC6125 and RFC6818 look to be decent starting points for what we should
aim for there, though support for them doesn't appear all that
widespread in other applications yet.

Thanks,

Nalin