Description of problem:
Vdsm quite often require last stable libvirt/qemu packages to make use of the last features. On CentOS/RHEL, the packages are updated after the release, so this is usually no issue. On Fedora, no updates besides bugfixes are given,
so one fedora release is stuck with one libvirt/qemu version far all its lifetime.

One given oVirt releases support current and past fedora releases; for example, the current fedora version is 24, the current ovirt version is 4.0, so ovirt 4.0 support both fedora 23 and 24.

So the lack of updated libvirt/qemu packages is an issue on fedora.
To mitigate this issue we informally recommended the usage of the virt-preview repository: https://fedoraproject.org/wiki/Virtualization_Preview_Repository

This repository provides updated packages for fedora. Those packages aren't stable like the standard ones; since we don't recommend fedora for production, this is not a real issue.

ovirt-release should support virt-preview, either always enabling it or providing the configuration disabled by default.
This is because we try hard NOT to always require virt-preview, but more often than not we need it.

At present day, both oVirt 4.1.z (to be released) and oVirt >= 4.0.6 will require libvirt >= 2.0, thus virt-preview repo on fedora 24.