Fix overrideSchedule Scheduler method name

[brenard]

In Schedule.set_schedule() method, the right method to call seem to be overrideSchedule instead of overridedSchedule (test and validate on my Livebox) as document here and also implement here. With the wrong method name, I have the following error :

{'status': None, 'errors': [{'error': 196618, 'description': 'Object or parameter not found', 'info': 'overridedSchedule'}]}