periodic_task should pop raise_on_error parameter so that it will not go to task function

[yong sheng gong]

def run_periodic_tasks(self, *args, **kwargs):
        """Tasks to be run at a periodic interval."""
        raise_on_error = kwargs.get('raise_on_error', False)

It should be kwargs.pop('raise_on_error', False)

[Davanum Srinivas (DIMS) (dims-v)]

looks like this is already fixed

https://github.com/openstack/oslo-incubator/commit/68fe32580ea4f7058bb15821566fa8ff10876ec5