Export a pipeline to json.

def export_pipeline(conf, args):
    """Export a pipeline to json."""
    # Export the source pipeline and save it to file
    src = conf.config['instances'][args.src_instance]
    src_url = api.build_pipeline_url(build_instance_url(src))
    src_auth = tuple([conf.creds['instances'][args.src_instance]['user'],
                      conf.creds['instances'][args.src_instance]['pass']])
    verify_ssl = src.get('verify_ssl', True)
    export_json = api.export_pipeline(src_url, args.src_pipeline_id, src_auth, verify_ssl)
    with open(args.out, 'w') as outFile:
        outFile.write(json.dumps(export_json, indent=4, sort_keys=False))
        return (0, '')