[Checkins] [zopefoundation/zope.app.folder] d9d4bd: Stop using deprecated --use-mirrors

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/zope.app.folder
  Commit: d9d4bd7fb0456ca2af45f00c51bfa544cdacaa44
      https://github.com/zopefoundation/zope.app.folder/commit/d9d4bd7fb0456ca2af45f00c51bfa544cdacaa44
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2015-11-08 (Sun, 08 Nov 2015)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Stop using deprecated --use-mirrors