Comment 1 for bug 1580222

The right package is installed, but only if the cinder-volume service is also running on a host that's also used to provide an LVM backend.
https://github.com/openstack/openstack-ansible-os_cinder/blob/master/tasks/cinder_install_apt.yml#L39-L50
https://github.com/openstack/openstack-ansible-os_cinder/blob/master/vars/ubuntu-14.04.yml#L33

We'll need to ensure that the qemu-img package is installed wherever the cinder-volume service is installed, regardless of the back-end. Alternatively we need to implement back-end specific package lists.