[Checkins] [zopefoundation/Persistence] d31dc9: - tweaks to appveyor config

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/Persistence
  Commit: d31dc94f940a5d2d1cf33b629988996149c9521b
      https://github.com/zopefoundation/Persistence/commit/d31dc94f940a5d2d1cf33b629988996149c9521b
  Author: Jens Vagelpohl <jens at netz.ooo>
  Date:   2017-11-27 (Mon, 27 Nov 2017)

  Changed paths:
    M appveyor.yml

  Log Message:
  -----------
  - tweaks to appveyor config