dns-root-data: simplify

pkgs/by-name/dn/dns-root-data/package.nix

@@ -5,7 +5,6 @@
 }:
 
 let
-
   rootHints = fetchurl {
     # Original source https://www.internic.net/domain/named.root
     # occasionally suffers from pointless hash changes,
@@ -16,12 +15,7 @@ let
     ];
     hash = "sha256-4lG/uPnNHBNIZ/XIeDM1w3iukrpeW0JIjTnGSwkJ8U4=";
   };
-
-  rootKey = ./root.key;
-  rootDs = ./root.ds;
-
 in
-
 stdenv.mkDerivation {
   pname = "dns-root-data";
   version = "2024-06-20";
@@ -29,8 +23,8 @@ stdenv.mkDerivation {
   buildCommand = ''
     mkdir $out
     cp ${rootHints} $out/root.hints
-    cp ${rootKey} $out/root.key
-    cp ${rootDs} $out/root.ds
+    cp ${./root.key} $out/root.key
+    cp ${./root.ds} $out/root.ds
   '';
 
   meta = with lib; {