Error handler for `shutil.rmtree()` equivalent to `rm -rf`.

    Usage: `shutil.rmtree(path, onerror=force_delete)`
    From stackoverflow.com/questions/1889597

def force_delete(func, path, exc_info):
    """Error handler for `shutil.rmtree()` equivalent to `rm -rf`.

    Usage: `shutil.rmtree(path, onerror=force_delete)`
    From stackoverflow.com/questions/1889597
    """
    os.chmod(path, stat.S_IWRITE)
    func(path)