This pulls in the code from https://github.com/openshift/os/pull/876/commits/dd35dd0e102aeed90df14f05c8ae9da4c8c5962a for the same reason.
We need this to access RHEL RPM content today. (I would like longer term to be able to fetch RPMs from registries with a pull secret, xref https://github.com/coreos/rpm-ostree/issues/4155 )