Ordinary release have Release values in the form of X.
Prereleases, e.g. release candidates, have Release values in the form 0.X.
I.e. following Fedora NVR (name, version, release) rules, _ordinary_
releases have NVRs like nfs-ganesha-2.0.0-X.fc21.x86_64.rpm, while
prereleases have NVRs like nfs-ganesha-2.0.0-0.X.rcY.fc21.x86_64.rpm.
This convention allows the GA updates to apply correctly when someone
has installed a prerelease RPM.
