Return absolute path for configuration file with specified filename.

def get_conf_path(filename=None):
    """Return absolute path for configuration file with specified filename."""
    conf_dir = osp.join(get_home_dir(), '.condamanager')

    if not osp.isdir(conf_dir):
        os.mkdir(conf_dir)

    if filename is None:
        return conf_dir
    else:
        return osp.join(conf_dir, filename)