message: mini documentation fix
diff: @@ -119,7 +119,7 @@ def confusion_matrix(labels, predictions, num_classes=None, dtype=dtypes.int32,
  For example:
  ```python
  - tf.contrib.metrics.confusion_matrix([1, 2, 4], [2, 2, 4]) ==>
  + tf.confusion_matrix([1, 2, 4], [2, 2, 4]) ==>
  [[0 0 0 0 0]
  [0 0 1 0 0]
  [0 0 1 0 0]
  