[Python-Dev] Fixing buildbot/external(-amd64).bat files on Windows

["Martin v. Löwis"]

>> -   vcbuild db-4.4.20\build_win32\Berkeley_DB.sln /build Debug /project db_static
>> +   devenv /upgrade db-4.4.20\build_win32\Berkeley_DB.sln
>> +   devenv db-4.4.20\build_win32\Berkeley_DB.sln /build Debug /project db_static
> 
> The upgrade is requires only once. It probably belongs next to the
> checkout or svn up and not in the build section.

I came up with yet another solution: I changed the repository to contain 
already the converted files (or, rather, made a copy, as the 2.5 branch
is still using the 7.1 project files):.

Regards,
Martin