Comment 32 for bug 1847361

The bad part on the apparmor block is that it is usually hard to change/reload per-guest profiles but that would be needed.
But well one thing at a time, for now adding an override:

in /etc/apparmor.d/local/abstractions/libvirt-qemu :
# let qemu load old shared objects after upgrades (LP: #1847361)
/{var/,}run/qemu/*/*.so mr,

With that it worked well.
I'll retest later with my ~ppa5 build and then it should be ready for an upstream discussion.