Fix input_dtype errors in pre-2.0 keras model H5FS files

fix_keras_model.py

import h5py
import shutil
import json
import sys


def fix_weight_file(model_path):
    with h5py.File(model_path, "r+") as out_h5:
        v = out_h5.attrs.get("model_config")
        config = json.loads(v)
        for i, l in enumerate(config["config"]["layers"]):
        dtype = l["config"].pop("input_dtype", None)
        if dtype is not None:
            l["config"]["dtype"] = dtype

        new_config_str = json.dumps(config)
        out_h5.attrs.modify("model_config", new_config_str)


if __name__ == '__main__':
    # Usage: fix_keras_model.py old_model.h5 new_model.h5
    input_model_path = sys.argv[1]
    output_model_path = sys.argv[2]
    shutil.copyfile(input_model_path, output_model_path)
    fix_weight_file(output_model_path)

    # Check that it worked.
    from keras.models import load_model
    load_model(output_model_path)