backout: backed out changeset 5d83a40cd3f8

Authored by Alphare.


backout: backed out changeset 5d83a40cd3f8

This is the re-send of the backout in D11757 that I accidentally queued. I'll
rewrite the original commit message:


We do not have Python 3 packaging for thg on Windows where the vast majority of
of users use the thg installer for Mercurial. Until this is done (hopefully
this cycle), we're keeping Python.

(end of the old commit message)

On top of this, we have a solid lead to have competent people take care of this
packaging issue for us in time for the 6.1 release, which is really the main
reason for us to wait. We're trying our best to make this work, so please bear
with us.

Differential Revision: https://phab.mercurial-scm.org/D11770