Comment 2 for bug 1620633

Document latest thoughts before context switching:

[15:54] <rbasak> cpaelzer: it looks like it can all be done in the XML - https://libvirt.org/formatstorage.html#StorageVolTarget has the definition, and the compat and feature/lazy_refcounts tags look relevant.
[15:55] <rbasak> cpaelzer: then in uvtool, uvtool/libvirt/kvm.py:create_cow_volume_by_path would be the function to change.
[15:55] <rbasak> I'm not sure how to decide on whether to enable compatiblity mode or not.
[15:56] <cpaelzer> I found the function, thanks for the spec pointer above
[15:57] <cpaelzer> rbasak: I'll hack it in locally to see if it even fixes the issue
[15:57] <cpaelzer> then we can think/decide further