[Python-Dev] MSI: Remove dependency from win32com.client module (issue4080047)

["Martin v. Löwis"]

> It is a surprise to find builtin msilib. Why isn't it used?

Originally, because Python needs to be packaged with an older
release (in particular one that isn't itself maintained anymore).
Today, the problem is that the msilib package doesn't support
merge modules (and if such support was added, we would have to
wait until the version containing it isn't maintained anymore).

I don't consider the dependency on win32com a serious issue at
all; it's just a mild annoyance (much less than reliance on ctypes
would be, or hard-coding of symbolic constants).

Regards,
Martin