The following commit adds the requirement - but I don't see the real need for it:
Date: Tue Jan 3 15:26:54 2017 +0100
Force usage of qemu-kvm-rhev on centos/rhel
Lago requires qemu-kvm >= 2.1.2, these are the required
package names for each distro:
CentOS: the package is named 'qemu-kvm-ev', but it provides
RHEL: named 'qemu-kvm-rhev'