Since the ostree repos are not available on the cdn yet, enabling them in the OSTree tab of the Red Hat Repositories page will (properly) show an error. However, some part of them has been partially created in pulp which causes error when user attempts to refresh manifest. In glue/pulp/repo.rb the lazy_accessor :importers will error on manifest refresh. The OSTree repo will show up as enabled in the UI but errors when trying to disable it. My suggestion would be to make sure that the initial enable is fully rolled back on an error.
Created from redmine issue http://projects.theforeman.org/issues/15516
I consider this a development environment issue and not a sat production issue, because Satellite customers will not get into this state. Basically without the --katello-enable-ostree=true customers will not be able to see OSTree repos that can be enabled. Its not the case in the dev environment and hence Tom hit that. Going to remove the flags out and mark it a non blocker. This should be addressed upstream only.