Made behavior of GaussianProcessHyperparamOpt more consistent

          f.write('\n')

      hp_str = _convert_hyperparam_dict_to_filename(hyper_parameters)

      if hp_str in all_results:

        # We have already evaluated the model for these hyperparameters.

        if use_max:

          return all_results[hp_str]

        else:

          return -all_results[hp_str]

      if logdir is not None:

        filename = "model%s" % hp_str

        model_dir = os.path.join(logdir, filename)