Update Fedora default mock config to use Rawhide
Update Fedora default mock config to use Rawhide

The current use case for DLRN in Fedora is mostly dedicated to
Rawhide, so it makes sense to make the default Fedora mock config
reflect that.

Change-Id: Iceb5a9be2a95ec3f48222f42b1aa21c581b49c20

openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN