Comment 22 for bug 1847361

Generated prerm code looks (at a first glimpse) as I'd expected it to be.
    remove|upgrade|deconfigure)
        # retain .so files for still running qemu instances in /var/run
        mkdir -p /var/run/qemu/1_4_2-3ubuntu2~ppa3
        cp /usr/lib/x86_64-linux-gnu/qemu/ui-gtk.so /usr/lib/x86_64-linux-gnu/qemu/audio-*.so /var/run/qemu/1_4_2-3ubuntu2~ppa3/
    ;;

On build time it will adapt:
- the arch to save
- the version path path.
- we are not going to consider co-installed architectures for this
  - the qemu load mechanism will block loading the wrong ones
  - it will not crash
  - just not gaining the benefit of this change for a non-real use case is ok)

Note: the first version had the code to save the files of qemu-system-gui in both packages, but is enough to test.