Revert of Removed virtualenv from depot_tools

bootstrap/gclient.bat

Index: bootstrap/gclient.bat
diff --git a/bootstrap/gclient.bat b/bootstrap/gclient.bat
new file mode 100644
index 0000000000000000000000000000000000000000..e79c088608cedf45997450eb7f618d34eb55a5ab
--- /dev/null
+++ b/bootstrap/gclient.bat
@@ -0,0 +1,22 @@
+@echo off
+:: Copyright (c) 2012 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.
+
+:: IMPORTANT NOTE:
+:: The bootstrap flow has been removed. This file's only purpose is to make the
+:: transition smooth as the previous update script called bootstrap\gclient.bat
+:: The current flow took place on March 21, 2012. This file should be removed
+:: when it is believed everyone has updated since then.
+
+:: At this point we know %DEPOT_TOOLS_UPDATE% != 0 as in the previous script
+:: bootstrap\gclient.bat was only called if this was the case.
+
+:: Update the root directory. The previous version only supported svn so there
+:: is no need looking for git here (i.e. if someone has git they can't get to
+:: this point where the bootstrap dir is gone during the update anyways...)
+IF NOT EXIST "%~dp0..\.svn\." GOTO :EOF
+call svn up -q "%~dp0.."
+
+:: Call the updated gclient.bat in the root directory to wrap the update.
+call "%~dp0..\gclient.bat"