title: Load TensorFlow FLAGS from file (TF version > 1.4)
body: <p>I would like to store <code>FLAGS</code> (<code>tf.app.flags.FLAGS</code>) in a file and reload them later. Until TensorFlow 1.4, I used this code for reloading:</p>
  
  <pre class="lang-py prettyprint-override"><code>with open(config_file, 'r') as f:
       config = json.load(f)
       FLAGS.__flags.update(config)
  </code></pre>
  
  <p>From TensorFlow 1.5, the underlying implementation of <code>FLAGS</code> changed. Does anybody know a way to update the FLAGS with values stored in a file?</p>