Plone 5.08 upgrade to 5.1 Error: Couldn’t find a distribution for ‘Plone==5.1.0’

[jaroel (Roel Bruggink)]

Buildout not working / Couldn't find index page for / Couldn't find a distribution / Disabling non HTTPS access to APIs on PyPI

Old versions of setuptools (0.6c11 in my case) will no longer work since access to pypi.python.org is hard coded on http. A simple change to https fixes the issue. We need a more permanent fix. Read about the change from the announcement: https://mail.python.org/pipermail/distutils-sig/2017-October/031712.html