fixes #8735 - enable config drive on Rackspace servers

    171152 #theforeman: < geek876> gwmngilfen: https://github.com/domcleal/foreman/compare/rackspace-cloud-init works.  Thanks

Useful tip when testing it.. if you can't get into the VM to check /var/log/cloud-init.log, you can reset the root password via the Rackspace control panel to get a password login.