automation: delete code related to Python 2.7 support
The building of Inno and WiX installers took a python_version argument
that allowed us to specify "2" or "3" for the major Python version. Since
we no longer support Python 2, we can delete this argument and everything
feeding into it.
Differential Revision: https://phab.mercurial-scm.org/D12264
$ hg init
$ echo a > a
$ hg ci -Ama
adding a
$ hg an a
0: a
$ hg --config ui.strict=False an a
0: a
$ echo "[ui]" >> $HGRCPATH
$ echo "strict=True" >> $HGRCPATH
$ hg an a
hg: unknown command 'an'
(use 'hg help' for a list of commands)
[10]
$ hg annotate a
0: a
should succeed - up is an alias, not an abbreviation
$ hg up
0 files updated, 0 files merged, 0 files removed, 0 files unresolved