message: Remove query_layer in LuongMonotonicAttention
  In the constructor for LuongMonotonicAttention, a query layer was being created but it was ultimately never used.
  Fixes
diff: @@ -924,8 +924,7 @@ class LuongMonotonicAttention(_BaseMonotonicAttentionMechanism):
  _monotonic_probability_fn, sigmoid_noise=sigmoid_noise, mode=mode,
  seed=sigmoid_noise_seed)
  super(LuongMonotonicAttention, self).__init__(
  - query_layer=layers_core.Dense(
  - num_units, name="query_layer", use_bias=False, dtype=dtype),
  + query_layer=None,
  memory_layer=layers_core.Dense(
  num_units, name="memory_layer", use_bias=False, dtype=dtype),
  memory=memory,
  