AD GPO: Always look up GPOs from machine domain
When dealing with users from a child domain, SSSD was attempting to use
the subdomain for lookups. However, all GPOs applicable to this machine
are stored in the primary domain (the domain the host directly joined).
This patch has the GPO processing use the primary domain instead of the
user domain.
Resolves:
https://fedorahosted.org/sssd/ticket/2606
Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
(cherry picked from commit 475d986b534c5e0dfdb8e2348ab89b13fd4874aa)