Comment 3 for bug 1685291

Marking CONFIG_SCSI_VIRTIO=y enables initrd-less boot on generic kernel, enabling any Ubuntu installation to be lifted from any hardware and converted into a VM which will, even with corrupted initrd and missing modules, be able to boot by default. This is an extremly useful property to have on all ubuntu kernels. Separately, this also removes the need for linux-kvm kernel flavour, as all the changes it has are now incorporated into generic flavour & cloud-images.