networkmanager: hardcode parts of the source URL (#67100)

Broke the build as the pname variable was used to create the URL
Introduced by 46420bbaa3f8f79ce7b9ee68e98eba1f7bce2db6

pkgs/tools/networking/network-manager/default.nix

···
 , openconnect, curl, meson, ninja, libpsl }:
 
 let
-  pname = "NetworkManager";
   pythonForDocs = python3.withPackages (pkgs: with pkgs; [ pygobject3 ]);
 in stdenv.mkDerivation rec {
   pname = "network-manager";
   version = "1.18.2";
 
   src = fetchurl {
-    url = "mirror://gnome/sources/${pname}/${stdenv.lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
+    url = "mirror://gnome/sources/NetworkManager/${stdenv.lib.versions.majorMinor version}/NetworkManager-${version}.tar.xz";
     sha256 = "1hx5dx5dgdqh3p8fq7q1pxy2bx2iymc74lj60ycrf7ydfjlprnad";
   };