If `qemu-vm.nix` is imported, the option `virtualisation.qemu.consoles`
should be set to make sure that the machine's output isn't rendered on
the graphical window of QEMU.
This is needed when interactively running a NixOS test or in conjunction
with `nixos-build-vms(8)`.
The patch 2578557530 tries to only do this
if the option actually exists, however this condition used to be always
false since `options` wasn't imported in the module and pointed to
`lib.options` due to the `with lib;`-clause.
2fbddb0ccb