'Deletes the QoS spec.
:param force: when force is True, all volume_type mappings for this QoS
are deleted.  When force is False and volume_type
mappings still exist, a QoSSpecsInUse exception is thrown'

def destroy(self, force=False):

    if self.volume_types:
        if (not force):
            raise exception.QoSSpecsInUse(specs_id=self.id)
        db.qos_specs_disassociate_all(self._context, self.id)
    updated_values = db.qos_specs_delete(self._context, self.id)
    self.update(updated_values)
    self.obj_reset_changes(updated_values.keys())
