Merge pull request #3038 from tensorflow/cifar10-outdated

Redirect users from cifar10 to cifar10_estimator

tutorials/image/cifar10/README.md

+**NOTE: For users interested in multi-GPU, we recommend looking at the newer [cifar10_estimator](https://github.com/tensorflow/models/tree/master/tutorials/image/cifar10_estimator) example instead.**
+
+---
+
 CIFAR-10 is a common benchmark in machine learning for image recognition.
 
 http://www.cs.toronto.edu/~kriz/cifar.html
@@ -7,4 +11,3 @@ Code in this directory demonstrates how to use TensorFlow to train and evaluate
 Detailed instructions on how to get started available at:
 
 http://tensorflow.org/tutorials/deep_cnn/
-