Comment 15 for bug 1913421

@Dan - from the discussion we had the outcome was that tmpfiles can only create directories and set ownership. At the same time the path is set (per upstream agreement cross distros) and also due to apparmor confinement no symlink magic will help. But the issue we ahve here is that we need to have /run/qemu to be NOT noexec which /run in many cases is by default.
I haven't seen any comeback of a tmpfiles solution as those limitations were not overcome.

If you strip out all the trial and error I had on this bug then it is just:
1. Victor told me we need "exec", he is right
2. Discussion with more developers showed that this feature, although nice - should
   really not be default enabled (but we are fine to make it a comfortable opt-in).
3. I'm prepping a change that fulfills
   #1 with a .mount unit
   #2 with a config file and the .mount being default disabled

The suggested config file would be:
/etc/default/qemu-block-extra-upgrade-backup

The files there usually are == package name, but this is a very special case so just naming it qemu-block-extra seems wrong. Starting with the package name, but having a suffix is what I'd go for until review happens.