Remove usage of nixFlakes

flake.nix

@@ -108,7 +108,7 @@
 
             deploy-local = lib.recurseIntoAttrs (lib.mapAttrs
               (hostname: machine: pkgs.writeShellScript "deploy-local-${hostname}" ''
-                ${pkgs.nixos-rebuild.override { nix = pkgs.nixFlakes; }}/bin/nixos-rebuild \
+                ${pkgs.nixos-rebuild}/bin/nixos-rebuild \
                     switch \
                     --flake .#${hostname} \
                     -L \

modules/default.nix

@@ -115,7 +115,7 @@
       };
 
       system.activationScripts.diff = ''
-        [ -L /run/current-system ] && ${pkgs.nixFlakes}/bin/nix \
+        [ -L /run/current-system ] && ${config.nix.package}/bin/nix \
             --experimental-features 'nix-command' \
             store \
             diff-closures /run/current-system "$systemConfig"