Comment 1 for bug 1575329

Recently upstream Horizon added a key to their default configuration in:
https://github.com/openstack/horizon/blob/1b65c5369fa70bfafe95ba5ff96d64661491868c/openstack_dashboard/settings.py#L82

This broke puppet deployments of Horizon because since puppet-horizon overrides the entire HORIZON_CONFIG dict (instead of setting each individual keys), we did not have that key and it yield a Horizon KeyError exception on images_panel.

+1 for config provider or something more flexible and especially not overriding the defaults provided by upstream