https://ask.openstack.org/en/question/28659/failure-login-to-dashboard-on-f20-havana-controller-after-recent-firefox-update-up-to-290-5/

This post was downgraded 12 hr ago. I did backport  F21 packages
to F20, to keep Horizon alive, nothing else.

> For details on the H -> I update process see:
> http://openstack.redhat.com/Upgrading_RDO_To_Icehouse
>
> thanks,
> Pádraig.