Code review comment for ~paelzer/ubuntu/+source/libvirt:merge-7.4.0-impish

One issue found that I could not resolve immediately, that one is for backward migrations (unsupported as sometimes they conceptually can't work). I filed an upstream issue https://gitlab.com/libvirt/libvirt/-/issues/179 to see if there might be anything better the long term, but that isn't blocking the uploads.

Furthermore I've spotted an issue in out copy-storage-inc handling, that worked by luck in the past, but it isn't libvirt/qemu that is bad - the test setup is it.

That explains all the issues I was seeing in regression tests so far.
We can go on evaluating this for an impish upload.