Run CWL with rabix bunny.

def _run_bunny(args):
    """Run CWL with rabix bunny.
    """
    main_file, json_file, project_name = _get_main_and_json(args.directory)
    work_dir = utils.safe_makedir(os.path.join(os.getcwd(), "bunny_work"))
    flags = ["-b", work_dir]
    log_file = os.path.join(work_dir, "%s-bunny.log" % project_name)
    if os.path.exists(work_dir):
        caches = [os.path.join(work_dir, d) for d in os.listdir(work_dir)
                  if os.path.isdir(os.path.join(work_dir, d))]
        if caches:
            flags += ["--cache-dir", max(caches, key=os.path.getmtime)]
    if args.no_container:
        _remove_bcbiovm_path()
        flags += ["--no-container"]
    cmd = ["rabix"] + flags + [main_file, json_file]
    with utils.chdir(work_dir):
        _run_tool(cmd, not args.no_container, work_dir, log_file)