[PATCH] msi: Remove system environment variables on uninstall.

[Marvin]

Hi,

While running your changed tests, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?

Full results can be found at:
https://testbot.winehq.org/JobDetails.pl?Key=51045

Your paranoid android.


=== w7u (32 bit report) ===

msi:
action: Timeout

=== w2008s64 (64 bit report) ===

msi:
action: Timeout