Deprecated model (#57)

change to tensorflow.python.ops since the model was deprecated

examples/3_NeuralNetworks/bidirectional_rnn.py

@@ -8,7 +8,7 @@ Project: https://github.com/aymericdamien/TensorFlow-Examples/
 '''
 
 import tensorflow as tf
-from tensorflow.models.rnn import rnn, rnn_cell
+from tensorflow.python.ops import rnn, rnn_cell
 import numpy as np
 
 # Import MINST data