fix typo in last commit (fix #1202)

examples/keras/mnist-keras.py

@@ -43,6 +43,7 @@ def get_keras_model():
     with clear_tower0_name_scope():
         M = keras.models.Sequential()
         M.add(KL.Conv2D(32, 3, activation='relu', input_shape=[IMAGE_SIZE, IMAGE_SIZE, 1], padding='same'))
+        M.add(KL.BatchNormalization())
         M.add(KL.MaxPooling2D())
         M.add(KL.Conv2D(32, 3, activation='relu', padding='same'))
         M.add(KL.Conv2D(32, 3, activation='relu', padding='same'))
@@ -68,7 +69,7 @@ class Model(ModelDesc):
         logits = M(image)
         if ctx.is_main_training_tower:
             for op in M.updates:
-                tf.add_to_collection(tf.GraphKeys.UPDATE_OPS)
+                tf.add_to_collection(tf.GraphKeys.UPDATE_OPS, op)
 
         # build cost function by tensorflow
         cost = tf.nn.sparse_softmax_cross_entropy_with_logits(logits=logits, labels=label)