TensorFlow: Upstream changes to git.

Change 109344341
	Teach ./configure about Python 3 (and other minor Python 3 issues)

	./configure now writes bazel.rc based on a bazel.rc.template, which gives us a
	place to tell bazel which version of Python we were using.

	Also fix a few tests whose Python 3 support had degraded.

	The only thing left before we have Python 3 support is

	  https://github.com/google/protobuf/pull/1023
Change 109343002
	Update ops.pbtxt to reflect 109321497.
Change 109342838
	Do memory deallocation outside the critical section in gpu_event_mgr.cc.
Change 109334210
	PTB LSTM example: use slicing instead of splitting the inputs.
Change 109332238
	Cleanup TensorBoard local development environment
Change 109331051
	Use __all__ in __init__.py to restrict exported modules

	Specifically, __all__ is now anything that (1) doesn't begin with an underscore
	and (2) isn't a non-whitelisted module.

	This fixes one tiny piece of b/25561952.  Specifically, the following no longer
	exist: tf.np, tf.math_ops, and tf.variables.  tf.ops and tf.tensor_util still
	exist but shouldn't; that will have to wait for a later CL.
Change 109327154
	tf.tuple allow Tensors to be passed in as control_inputs like tf.control_dependencies.
Change 109324239
	Make tf.control_dependencies(None) clear the control dependencies.
	Use that to prevent ops created for Variables to inherit the current
	control dependencies.

	This fixes issues when using ExponentialMovingAverages with control
	dependencies.
Change 109323719
	Added support for boolean tf.scatter_update.

Base CL: 109348398
diff --git a/util/python/python_config.sh b/util/python/python_config.sh
index 27b2094..dae1577 100755
--- a/util/python/python_config.sh
+++ b/util/python/python_config.sh
@@ -45,6 +45,12 @@
     exit 1
   fi
 
+  local python_major_version=$("${PYTHON_BIN_PATH}" -c 'from __future__ import print_function; import sys; print(sys.version_info[0]);')
+  if [ "$python_major_version" == "" ]; then
+    echo -e "\n\nERROR: Problem getting python version.  Is $PYTHON_BIN_PATH the correct python binary?"
+    exit 1
+  fi
+
   local python_include=$("${PYTHON_BIN_PATH}" -c 'from __future__ import print_function; from distutils import sysconfig; print(sysconfig.get_python_inc());')
   if [ "$python_include" == "" ]; then
     echo -e "\n\nERROR: Problem getting python include path.  Is distutils installed?"
@@ -70,6 +76,12 @@
   ln -s "${python_include}" util/python/python_include
   ln -s "${python_lib}" util/python/python_lib
   ln -s "${numpy_include}" third_party/py/numpy/numpy_include
+
+  # Write tools/bazel.rc
+  echo "# Autogenerated by configure: DO NOT EDIT" > tools/bazel.rc
+  sed -e "s/\$PYTHON_MAJOR_VERSION/$python_major_version/g" \
+      -e "s[\$PYTHON_BINARY[$PYTHON_BIN_PATH[g" \
+      tools/bazel.rc.template >> tools/bazel.rc
 }
 
 function check_python {