title: tf.set_random_seed doesn't seem to set the seed correctly
body: <p>I encountered a problem that <code>tf.set_random_seed</code> is unable to generate a repeatable value when programming using Tensorflow on python. To be specific, </p>
  
  <pre><code>import tensorflow as tf
  sd = 1
  tf.set_random_seed(seed = sd)
  
  tf.reset_default_graph()
  sess = tf.InteractiveSession()
  print(sess.run(tf.random_normal(shape=[1], mean=0, stddev=1)))
  </code></pre>
  
  <p>the code above outputs <code>[1.3086201]</code>. Then I ran the whole piece of code again, it doesn't outputs the expected value <code>[1.3086201]</code> but gives a new <code>[-2.1209881]</code>. </p>
  
  <p>Why would this happen and how to set a Tensorflow seed?</p>