Code review comment for ~rafaeldtinoco/ubuntu/+source/qemu:lp1828495-bionic-devel-qemu

#13 - this only changes code that is present and active post qemu 3.1.
It does set compat of 3.1 to off (which is wrong, needs to be on I think) and the named types.
I know this is a uncommon and deprecated feature, but we don't even have to touch it.

This should be a no-op at best for 2.11-3.1 and worst case a bug.
Please drop this patch completely for this backport effort.