TYPE_QAUTHZ is an abstract object of type TYPE_OBJECT. All other
are children of TYPE_QAUTHZ, thus also objects.

Keep INTERFACE_CHECK() for interfaces, and use OBJECT_CHECK() on
objects.

Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>