nixos-build-vms: use the driverInteractive attribute instead

This reverts commit aab534b894 & uses the
driverInteractive attribute for the test driver instead.

This has the same effect but removes the extra module in the
nixos-build-vms code.

nixos/modules/installer/tools/nixos-build-vms/build-vms.nix

@@ -6,12 +6,7 @@
 let
   nodes = builtins.mapAttrs (vm: module: {
     _file = "${networkExpr}@node-${vm}";
-    imports = [
-      module
-      ({ pkgs, ... }: {
-        virtualisation.qemu.package = pkgs.qemu;
-      })
-    ];
+    imports = [ module ];
   }) (import networkExpr);
 in
 
@@ -20,4 +15,4 @@ with import ../../../../lib/testing-python.nix {
   pkgs = import ../../../../.. { inherit system config; };
 };
 
-(makeTest { inherit nodes; testScript = ""; }).driver
+(makeTest { inherit nodes; testScript = ""; }).driverInteractive