title: Converting Tensorflow Frozen Graph to UFF for TensorRT inference
body: <p>I want to use a tensorflow model with TensorRT (C++) and first need to convert the the .pb to .uff format. When executing this code:</p>
  
  <pre><code>uff_model = uff.from_tensorflow_frozen_model(
    frozen_file="my_tf_model.pb",
    output_nodes=["output_layer"],
    output_filename="tmp.uff",
    debug_mode=True,
  )
  </code></pre>
  
  <p>I am getting this error message:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/home/jodo/ILONA/object-detection/ssd/src/uff_converter/uff_converter.py", line 29, in &lt;module&gt;
      text=False,
    File "/home/jodo/miniconda3/envs/uff_converter/lib/python3.7/site-packages/uff/converters/tensorflow/conversion_helpers.py", line 228, in from_tensorflow_frozen_model
      graphdef.ParseFromString(frozen_pb.read())
  google.protobuf.message.DecodeError: Error parsing message
  </code></pre>
  
  <p>The exported graph (my_tf_model.pb) was trained and saved with tensorflow 2.0.0. But for the uff converter I have to use tensorflow 1.15.0. Could this be an issue or should the .pb file be downwards compatiable?</p>
  
  <p><strong>Update</strong>: Tested with a model trained with the same version as uff converter is used (1.15.0) and still same error.</p>