message: Initialize fetchTensors to fix NullPointerException
  closeFetches() needs fetchTensors to not be null. fetchTensors is initialized by run() and the first thing run() does is call closeFetches().
diff: @@ -616,7 +616,7 @@ public class TensorFlowInferenceInterface {
  private List<String> feedNames = new ArrayList<String>();
  private List<Tensor<?>> feedTensors = new ArrayList<Tensor<?>>();
  private List<String> fetchNames = new ArrayList<String>();
  - private List<Tensor<?>> fetchTensors = null;
  + private List<Tensor<?>> fetchTensors = new ArrayList<Tensor<?>>();
  // Mutable state.
  private RunStats runStats;
  