Stop a pipeline.

def stop_pipeline(conf, args):
    """Stop a pipeline."""
    host = conf.config['instances'][args.host_instance]
    url = api.build_pipeline_url(build_instance_url(host))
    auth = tuple([conf.creds['instances'][args.host_instance]['user'], conf.creds['instances'][args.host_instance]['pass']])
    verify_ssl = host.get('verify_ssl', True)

    stop_result = api.stop_pipeline(url, args.pipeline_id, auth, verify_ssl)
    return stop_result