title: Tensorboard error after upgrading to 1.4: trying to access flag before flags were parsed
body: <p>Since upgrading to TF 1.4 I am getting this error when I try to run <code>tensorboard</code>:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/opt/python/3.6.3/bin/tensorboard", line 11, in &lt;module&gt;
      sys.exit(main())
    File "/opt/python/3.6.3/lib/python3.6/site-packages/tensorboard/main.py", line 39, in main
      return program.main(default.get_plugins(),
    File "/opt/python/3.6.3/lib/python3.6/site-packages/tensorboard/default.py", line 71, in get_plugins
      debugger = debugger_plugin_loader.get_debugger_plugin()
    File "/opt/python/3.6.3/lib/python3.6/site-packages/tensorboard/plugins/debugger/debugger_plugin_loader.py", line 46, in get_debugger_plugin
      if FLAGS.debugger_data_server_grpc_port is None:
    File "/opt/python/3.6.3/lib/python3.6/site-packages/absl/flags/_flagvalues.py", line 509, in __getattr__
      raise _exceptions.UnparsedFlagAccessError(error_message)
  absl.flags._exceptions.UnparsedFlagAccessError: Trying to access flag --debugger_data_server_grpc_port before flags were parsed.
  </code></pre>
  
  <p>I am getting this error even when just typing <code>tensorboard</code> with no <code>--logdir</code> specified but also when I do specify a log dir. I notice this has been reported in github as of 5 days ago (<a href="https://github.com/tensorflow/nmt/issues/176" rel="nofollow noreferrer">https://github.com/tensorflow/nmt/issues/176</a>), but I am surprised not to see more folks reporting this.</p>
  
  <p>I also noticed that I was not able to run a Tensorflow RNN tutorial for the same reason last week, with the error also indicating flags were accessed before being parsed. Has anyone run into this and  can you tell me if there's a fix?</p>