title: Restore variable in tensorflow without specifying its shape
body: <p>I can restore a variable this way in tensorflow:</p>
  
  <pre><code>with tf.Session() as sess:
      var = tf.Variable([6, 7])
      tf.train.Saver({'name': pvdm_train}).restore(sess, 'model.ckpt'))
  </code></pre>
  
  <p>But how do I restore it if the shape is unknown? This is quite helpful when I want to just load a variable and use it to say perform classification.</p>