fix scaler transform boston skflow example (tensorflow#2152)

fit_transform was being used instead of transform for the test set in the boston example

Author: mheilman

tensorflow/examples/skflow/boston.py

@@ -40,6 +40,6 @@
 regressor.fit(X_train, y_train)
 
 # Predict and score
-score = metrics.mean_squared_error(regressor.predict(scaler.fit_transform(X_test)), y_test)
+score = metrics.mean_squared_error(regressor.predict(scaler.transform(X_test)), y_test)
 
 print('MSE: {0:f}'.format(score))