message: Remove initial accumulator (and other auxiliary parameter) values from
  optimization parameter protos and removed uses of that functionality in tests.
diff: @@ -28,7 +28,6 @@ message LearningRate {
  // https://www.tensorflow.org/api_docs/python/tf/train/AdagradOptimizer
  // https://github.com/tensorflow/tensorflow/blob/c19e29306ce1777456b2dbb3a14f511edf7883a8/tensorflow/core/kernels/training_ops.cc#L151
  message AdagradParameters {
  - float initial_accumulator = 1;
  }
  // https://www.tensorflow.org/api_docs/python/tf/train/GradientDescentOptimizer
  @@ -42,8 +41,6 @@ message FtrlParameters {
  float l1 = 1;
  float l2 = 2;
  float lr_power = 3;
  - float initial_accum = 4;
  - float initial_linear = 5;
  }
  // The Adam optimizer does not implement hyper-parameter update; use the dynamic
  @@ -70,8 +67,6 @@ message AdamParameters {
  float beta1 = 3;
  float beta2 = 4;
  float epsilon = 5;
  - float initial_m = 6;
  - float initial_v = 7;
  bool use_non_lazy_adam = 8;
  bool use_max_with_epsilon = 9;
  }
  @@ -81,7 +76,6 @@ message AdamParameters {
  message MomentumParameters {
  float momentum = 1;
  bool use_nesterov = 2;
  - float initial_accum = 3;
  }
  // https://www.tensorflow.org/api_docs/python/tf/train/RMSPropOptimizer
  @@ -90,8 +84,6 @@ message RmsPropParameters {
  float rho = 1;
  float momentum = 2;
  float epsilon = 3;
  - float initial_ms = 4;
  - float initial_mom = 5;
  }
  // https://www.tensorflow.org/api_docs/python/tf/train/RMSPropOptimizer
  @@ -100,9 +92,6 @@ message CenteredRmsPropParameters {
  float rho = 1;
  float momentum = 2;
  float epsilon = 3;
  - float initial_ms = 4;
  - float initial_mom = 5;
  - float initial_mg = 6;
  }
  // Variant of algorithm in http://proceedings.mlr.press/v44/shamir15.pdf
  @@ -119,9 +108,6 @@ message MdlAdagradLightParameters {
  float mdl_hard_limit = 10;
  bool hard_limit_min_benefit = 11;
  bool mdl_regularize = 12;
  - float initial_accumulator = 13;
  - float initial_weight = 14;
  - float initial_benefit = 15;
  }
  // https://www.tensorflow.org/api_docs/python/tf/train/RMSPropOptimizer
  @@ -129,8 +115,6 @@ message MdlAdagradLightParameters {
  message AdadeltaParameters {
  float rho = 1;
  float epsilon = 2;
  - float initial_accumulator = 3;
  - float initial_update = 4;
  }
  // https://www.tensorflow.org/api_docs/python/tf/train/RMSPropOptimizer
  @@ -138,7 +122,6 @@ message AdadeltaParameters {
  message ProximalAdagradParameters {
  float l1 = 1;
  float l2 = 2;
  - float initial_accumulator = 3;
  }
  message OptimizationParameters {
  