polkit WIP: resurrect the forgotten polkituser

It needs no group anymore. I hope it won't clash with leftovers from
previous usage of the user.

nixos/modules/misc/ids.nix

@@ -140,7 +140,7 @@
       tape = 25;
       video = 26;
       dialout = 27;
-      polkituser = 28;
+      #polkituser = 28; # currently unused, polkitd doesn't need a group
       utmp = 29;
       davfs2 = 31;
       privoxy = 32;

nixos/modules/security/polkit.nix

@@ -95,6 +95,12 @@ in
         # configuration.
         ${pkgs.procps}/bin/pkill -INT -u root -x polkitd
       '';
+
+    users.extraUsers.polkituser = {
+      description = "PolKit daemon";
+      uid = config.ids.uids.polkituser;
+    };
+
   };
 
 }