[PATCH 5 of 8] import-checker: skip site-packages for virtualenv

[Yuya Nishihara]

On Wed, 30 Mar 2016 04:24:05 -0500, timeless wrote:
> # HG changeset patch
> # User timeless <timeless at mozdev.org>
> # Date 1459325405 0
> #      Wed Mar 30 08:10:05 2016 +0000
> # Node ID 54b962661f75e4a55c213c0eeb30f5d6024f7dbe
> # Parent  9bdba93f0afd6ffe087663510f5198fdb8e40536
> import-checker: skip site-packages for virtualenv
> 
> pygments was being treated as a stdlib...

If I understand it, pygments should be treated as a stdlib. stdlib_modules is
used to sort out system-installed modules from our modules.