libxl__spawn_confirm_offspring_startup() is a generic version of
libxl__confirm_device_model_startup().
Use libxl__spawn_confirm_offspring_startup for device model.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Jackson <ian.jackson.citrix.com>
Committed-by: Ian Jackson <ian.jackson.citrix.com>