Comment 2 for bug 1624791

The issue is fixed when we remove pyopenssl from the horizon containers:

ansible -i inventory -m shell -a 'apt remove -y python-openssl; service apache2 restart' horizon_all

Root cause: https://github.com/shazow/urllib3/issues/367

Which is an issue which is open since 2014 without a fix.

See also: https://github.com/kennethreitz/requests/issues/2543 and http://stackoverflow.com/a/38236543