Reasoning:
- Setting custom properties on glance images allows us to select the
type of disk bus e.g. VIRTIO/IDE/SCSI.
Although SATA disk bus works perfectly for qemu/kvm, it is not allowed
due to a check in virt/libvirt/blockinfo.py : is_disk_bus_valid_for_virt
- some Linux (custom) images require use of SATA bus rather than any
other that seems to be allowed.
Change-Id: Ie32ff7acf31d80d4fc1adbeadaaf30a886d10e49
Closes-Bug: #1686136