lstm: Remove unused constant and unused local variables

This fixes three compiler warnings.

Signed-off-by: Stefan Weil <sw@weilnetz.de>

lstm/lstmtrainer.cpp

@@ -55,8 +55,6 @@ const int kNumPagesPerBatch = 100;
 const int kMinStartedErrorRate = 75;
 // Error rate at which to transition to stage 1.
 const double kStageTransitionThreshold = 10.0;
-// How often to test for flipping.
-const int kFlipTestRate = 20;
 // Confidence beyond which the truth is more likely wrong than the recognizer.
 const double kHighConfidence = 0.9375;  // 15/16.
 // Fraction of weight sign-changing total to constitute a definite improvement.
@@ -856,7 +854,6 @@ Trainability LSTMTrainer::PrepareForBackward(const ImageData* trainingdata,
     return UNENCODABLE;
   }
   targets->Resize(*fwd_outputs, network_->NumOutputs());
-  double text_error = 100.0;
   LossType loss_type = OutputLossType();
   if (loss_type == LT_SOFTMAX) {
     if (!ComputeTextTargets(*fwd_outputs, truth_labels, targets)) {

lstm/networkio.cpp

@@ -553,7 +553,6 @@ void NetworkIO::EnsureBestLabel(int t, int label) {
     // remainder to best_label.
     int num_classes = NumFeatures();
     float* targets = f_[t];
-    float enhancement = (1.0f - targets[label]) / 3.0f;
     for (int c = 0; c < num_classes; ++c) {
       if (c == label) {
         targets[c] += (1.0 - targets[c]) * (2 / 3.0);