Update pointer to python "executable" for cygwin extension docs updater script.

chrome/common/extensions/docs/build/build.sh

 #!/bin/sh
 
-# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 BUILD_DIR=$(dirname "$0")
 
 function depot_tools_error() {
   echo "Cannot find depot_tools python - is it installed and in your path?" 1>&2
   exit 1
 }
 
 if [ "$(uname | cut -b1-6)" == "CYGWIN" ] ; then
   # On cygwin, we use the verison of python from depot_tools.
   echo "Detected cygwin - looking for python in depot_tools"
   GCLIENT_PATH=$(which gclient)
   if ! [ -f "$GCLIENT_PATH" ] ; then
     depot_tools_error
   fi
   DEPOT_TOOLS=$(dirname "$GCLIENT_PATH")
-  PYTHON_PATH="$DEPOT_TOOLS/python"
+  PYTHON_PATH="$DEPOT_TOOLS/python.bat"
   if ! [ -f "$PYTHON_PATH" ] ; then
     depot_tools_error
   fi
 
   # The output from build.py doesn't seem seem to print to the console until
   # it's finished, so print a message so people don't think it's hung.
   echo "Running - this can take about a minute"
   echo "(it goes faster if you have a Release build of DumpRenderTree)"
 
   $PYTHON_PATH $BUILD_DIR/build.py $*
 else
   # On all other platforms, we just run the script directly.
   $BUILD_DIR/build.py $*
 fi