tf_upgrade_v2 for blueoil/layers

[ytfksw]

What this patch does to fix the issue.

I converted blueoil/layer with the command line tool tf_upgrade_v2 to run on tensorflow2.

Since tf.contrib is not supported, I change it manually.

Here's what I did:

1. install newest tenosrflow (tensorflow-gpu==1.5.2)
2. Run the upgrade script tf_upgrade_v2
3. convert tf.contrib manually
   • tf.contrib.layers.batch_norm -> tf.compat.v1.layers.batch_normalization
   • tf.contrib.layers.fully_connected -> tf.keras.layers.Dense
4. Check the upgrade report for warnings and errors
5. Run test (make test)
6. [WIP] Make sure there is no change in accuracy

Link to any relevant issues or pull requests.

• Consider upgrading to TensorFlow 2.0 #479
• https://www.tensorflow.org/guide/upgrade

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