Add QtMacExtras_stable to the integrators subscribe list

Change-Id: Id23abf18f8744e2c87d86d69b9217d0def28948d
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Add QtWinExtras_stable to the integrator's subscribe list

Change-Id: Idc68caf071a0322d18abad059dea9b6966720103
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>