[PATCH 4 of 4 py3] contrib: add a ratchet for tests in Python 3

[Yuya Nishihara]

On Fri, 16 Jun 2017 09:38:52 -0400, Augie Fackler wrote:
> 
> > On Jun 16, 2017, at 9:28 AM, Yuya Nishihara <yuya at tcha.org> wrote:
> > 
> > Perhaps you would mean (3, 5) <= sys.version_info ?
> 
> Crud, yes I do. Do you want a resend, or should one of us just fix it with a quick amend and push?

It's still in my local repo, so fixed at my end.