Don't handle object_property_get_link() failure that can't happen
unless the programmer screwed up, pass &error_abort.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200707160613.848843-25-armbru@redhat.com>