heimdal Fix handling of backwards cross-realm detection for Samba4

heimdal Fix handling of backwards cross-realm detection for Samba4

Samba4 may modify the case of the realm in a returned entry, but will no longer modify the case of the prinicipal components.

The easy way to keep this test passing is to consider also what we
need to do to get the krbtgt account for the PAC signing - and to use
krbtgt/<this>/@REALM component to fetch the real krbtgt, and to use
that resutl for realm comparion.

Andrew Bartlett

Autobuild-User: Andrew Bartlett <abartlet@samba.org>
Autobuild-Date: Mon Nov 15 08:47:44 UTC 2010 on sn-devel-104