fix cmake python 2.7 test import fail

tensorflow/__init__.py

@@ -28,7 +28,8 @@ contrib = LazyLoader('contrib', globals(), 'tensorflow.contrib')
 del LazyLoader
 
 from tensorflow.python.platform import flags  # pylint: disable=g-import-not-at-top
-app.flags = flags  # pylint: disable=undefined-variable
+from tensorflow.python.platform import app  # pylint: disable=g-import-not-at-top
+app.flags = flags
 
 del absolute_import
 del division

tensorflow/contrib/cmake/python_modules.txt

@@ -4,6 +4,8 @@ tensorflow
 tensorflow/core
 tensorflow/core/example
 tensorflow/core/framework
+tensorflow/core/kernels
+tensorflow/core/kernels/boosted_trees
 tensorflow/core/lib
 tensorflow/core/lib/core
 tensorflow/core/profiler