title: tf.contrib.learn tutorial deprecation warning
body: <p>I am just wondering what's the preferred method to refactor the code in the tf.contrib.learn <a href="https://www.tensorflow.org/tutorials/tflearn/" rel="nofollow noreferrer">tutorial</a> to remove the following warning in tensorflow 0.12:</p>
  
  <pre><code>Estimator is decoupled from Scikit Learn interface by moving into
  separate class SKCompat. Arguments x, y and batch_size are only
  available in the SKCompat class, Estimator will only accept input_fn.
  Example conversion:
  est = Estimator(...) -&gt; est = SKCompat(Estimator(...))
  </code></pre>
  
  <p>Looking at the code, DNNClassifier cannot take a custom Estimator, and the fit method calls</p>
  
  <pre><code>    self._estimator.fit(x=x,
                      y=y,
                      input_fn=input_fn,
                      steps=steps,
                      batch_size=batch_size,
                      monitors=hooks,
                      max_steps=max_steps)
  </code></pre>
  
  <p>which triggers the warning, even if x, y and batch_size are not passed to the fit method.</p>