Hi,
as you probably noticed, CentOS 7.3 is rolling out right now and will be announced pretty soon.
Please note that due to new libvirt shipped within CentOS 7.3, it is required to update qemu-kvm-ev to 2.6 at the same time.

If you're using CentOS Virt SIG rpms / repos for oVirt this should happen automatically. 
If you're using only ovirt repositories be sure to have qemu-kvm-ev 2.6 if you update to CentOS 7.3.

In terms of ovirt repositories, qemu-kvm-ev 2.6 is available right now in ovirt-master-snapshot-static, ovirt-4.0-snapshot-static, and ovirt-4.0-pre (contains 4.0.6 RC4 rpms going to be announced in a few minutes.)

Thanks,
--
Sandro Bonazzola
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