Adding to base hparams the attributes for for librispeech.

def add_librispeech_hparams(hparams):
  """Adding to base hparams the attributes for for librispeech."""
  hparams.batch_size = 36
  hparams.audio_compression = 8
  hparams.hidden_size = 2048
  hparams.max_input_seq_length = 600000
  hparams.max_target_seq_length = 350
  hparams.max_length = hparams.max_input_seq_length
  hparams.min_length_bucket = hparams.max_input_seq_length // 2
  hparams.learning_rate = 0.05
  hparams.train_steps = 5000000
  hparams.num_hidden_layers = 4
  return hparams