title: Error in converting model into Tensorflow-lite
body: <p>I have trained a custom model using DNN and tried to use TF_Lite for using that in Android. I'm using the same method in the demo app for loading the asset file. </p>
  
  <pre><code>private MappedByteBuffer loadModelFile() throws IOException {
  AssetFileDescriptor fileDescriptor = getAssets().openFd(getModelPath());
  FileInputStream inputStream = new FileInputStream(fileDescriptor.getFileDescriptor());
  FileChannel fileChannel = inputStream.getChannel();
  long startOffset = fileDescriptor.getStartOffset();
  long declaredLength = fileDescriptor.getDeclaredLength();
  return fileChannel.map(FileChannel.MapMode.READ_ONLY, startOffset, declaredLength);
  </code></pre>
  
  <p>But I'm getting following error.</p>
  
  <pre><code>E/AndroidRuntime: FATAL EXCEPTION: main Process: revan.locationspeed,     
  PID: 12072 java.lang.RuntimeException: Unable to start activity     
  ComponentInfo{revan.locationspeed/thambu.locationspeed.MainActivity}:     
  java.lang.IllegalArgumentException: Contents of /dnn_frozen_graph.tflite     
  does not encode a valid TensorFlowLite model: Could not open '/dnn_frozen_graph.tflite'.The model is not a valid Flatbuffer file. 
  Caused by: java.lang.IllegalArgumentException: Contents of /dnn_frozen_graph.tflite does not encode a valid TensorFlowLite model: 
  Could not open '/dnn_frozen_graph.tflite'.The model is not a valid Flatbuffer file.
  </code></pre>
  
  <p>I used toco for conversion... A single Activity Class in Android.</p>