[PATCH 3 of 3 v2 pip-fix] tests: add a test for installing hg with pip in a virtualenv

[Yuya Nishihara]

On Thu, 08 Jun 2017 21:01:07 -0400, Matt Harbison wrote:
> On Thu, 08 Jun 2017 10:52:10 -0400, Augie Fackler <raf at durin42.com> wrote:
> 
> > # HG changeset patch
> > # User Augie Fackler <augie at google.com>
> > # Date 1496762198 14400
> > #      Tue Jun 06 11:16:38 2017 -0400
> > # Node ID ef19f4139ca98d49f50677a7465cb5e750dbce60
> > # Parent  510ffdb1a28bf8acab7ebe9d2c79af4555ac398e
> > tests: add a test for installing hg with pip in a virtualenv
> 
> LGTM, thanks!

Queued per review, thanks.