Set up neutron credentials

def _auth(profile=None):
    '''
    Set up neutron credentials
    '''
    credentials = __salt__['config.option'](profile)
    kwargs = {
        'username': credentials['keystone.user'],
        'password': credentials['keystone.password'],
        'tenant_name': credentials['keystone.tenant'],
        'auth_url': credentials['keystone.auth_url'],
        'region_name': credentials.get('keystone.region_name', None),
        'service_type': credentials['keystone.service_type'],
    }

    return suoneu.SaltNeutron(**kwargs)