Update the python auto-install on Windows to 2.7.6.

Update the python auto-install on Windows to 2.7.6.

2.7.5 has bug http://bugs.python.org/issue17998 in re package that is affecting
the chromium team so it can't be used. The bug is fixed in 2.7.6.

This update still respects DEPOT_TOOLS_PYTHON_275=0. Since the name doesn't
represent what is being installed, it also respects
DEPOT_TOOLS_PYTHON_27=0.

R=iannucci@chromium.org
BUG=241769
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=235384

[M-A Ruel, 2013-11-15 16:25:17]

The zip was added earlier today in r235340.

As a reference, here's the content of README.chromium embedded in
python276_bin.zip:

--- CUT HERE ---
This document contains instructions to recreate this archive.

Overview:
- First python is installed.
- The necessary system dlls are copied into the python27 directory.
- Then easy-install, pip, pywin32 and psutil are installed.
- Cleanup to reduce package size.
- Packaging and cleanup.

Exact steps:
- http://www.python.org/download, chose "Python 2.7.5 Windows Installer"
  - Install for all uses, deselect "Tcl/Tk", "Documentation", "Test suite"
- http://www.dependencywalker.com, load python.exe into depends.exe to figure
  which dependencies are needed
  - Copy c:\windows\syswow64\python27.dll to c:\python27
  - Copy
c:\windows\winsxs\x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.6161_none_50934f2ebcb7eb57\MSVCR90.DLL
    to c:\python27. Note the exact path may change in the future.
- http://www.pip-installer.org/en/latest/installing.html#python-os-support
  Exact url was https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py
  - Run "c:\python27\python ez_setup.py" under Elevated prompt (run as admin)
- Download pip from https://github.com/pypa/pip/tree/master/contrib
  Exact url is https://raw.github.com/pypa/pip/master/contrib/get-pip.py
  - Run "c:\python27\python.exe get-pip.py" under Elevated prompt (run as admin)
- Take latest build at http://sourceforge.net/projects/pywin32/files/pywin32/
  Exact url is
http://sourceforge.net/projects/pywin32/files/pywin32/Build%20218/pywin32-218...
  - Choose pywin32-218.win32-py2.7.exe and run it.
  - Move c:\python27\Lib\site-packages\pywin32_system32 back to c:\python27
- Install psutil from pypi;
https://pypi.python.org/pypi?:action=display&name=psutil#downloads
  Exact url is
https://pypi.python.org/packages/2.7/p/psutil/psutil-1.1.3.win32-py2.7.exe#md...
  - Run it.
- Copy this file (README.chromium) into C:\python27
- Copy python.exe to python_slave.exe; chromium specific for buildbot slaves
- Delete psutil-wininst.log, pywin32-wininst.log, Removepsutil.exe,
  Removepywin32.exe, w9xpopen.exe.
- Delete lib\test, lib\lib-tk, lib\site-packages\PyWin32.chm
- Run "del /s c:\python27\*.pyc"
- For each script in c:\python27\Scripts\*.py:
  - Replace the shebang with "#!python.exe" to remove the absolute path.
- Copy (not rename) c:\python27 to python276_bin somewhere else and use Windows
  Explorer to compress the directory
- Control Panel, Programs and Features, uninstall:
  - Python 2.7 psutil (it'll fail but it's fine)
  - Python 2.7 pywin32 (it'll fail but it's fine)
  - Python 2.7.6
- Delete all files starting with python in c:\windows\syswow64.
  - Watch out to not mess your installation up.
- Delete c:\python27
- Make sure it works, go in your copy and run:
  - python -c "import win32api, psutil"

If running on a vanilla Windows XP installation, the
"Microsoft Visual C++ 2008 Redistributable Package (x86)" must be installed.
https://microsoft.com/download/details.aspx?id=29
--- CUT HERE ---

[iannucci, 2013-11-15 18:37:32]

lgtm. Pretty unbelievable that 1) This bug exists, 2) We actually hit it.

[M-A Ruel, 2013-11-15 18:39:52]

Committed patchset #1 manually as r235384.