message: fix command line example package path
diff: @@ -41,7 +41,7 @@ FlatBuffer to perform floating-point inference.
  ```
  bazel run --config=opt \
  - third_party/tensorflow/contrib/lite/toco:toco -- \
  + //tensorflow/contrib/lite/toco:toco -- \
  --savedmodel_directory=/tmp/saved_model \
  --output_file=/tmp/foo.tflite
  ```
  