wix: remove enum and future packages
These were cargo culted from the THG installer code. I'm not sure
what needs them in THG land. But the official MSIs certainly do
not - at least not as direct dependencies.
.. bc::
The Windows MSI installers no longer include the enum and future
Python packages.
Differential Revision: https://phab.mercurial-scm.org/D6101
$ hg init
$ echo This is file a1 > a
$ hg add a
$ hg commit -m "commit #0"
$ ls
a
$ echo This is file b1 > b
$ hg add b
$ hg commit -m "commit #1"
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
B should disappear
$ ls
a