'From the private buildbot configuration, construct a list of all of the
libcloud drivers where leaked volumes might be found.'

def _get_cloud_drivers(self, config):

    base_ec2 = config['aws']
    drivers = [get_rackspace_driver(config['rackspace']), get_ec2_driver(base_ec2)]
    for extra in config.get('extra-aws', []):
        extra_driver_config = base_ec2.copy()
        extra_driver_config.update(extra)
        drivers.append(get_ec2_driver(extra_driver_config))
    return drivers
