This has no functional change on Buster, but on Bullseye this overrides
the stupid socket-based activation shenanigans that the default unit
tries to do, as well as the breaking replacement of the
/etc/default/libvirt variable names.
I figured a * wildcard would work, but no it doesn't. Libvirt needs
the ability to talk to any pool arbitrarily since PVC can create and
remove them at will.
Joshua Boniface