update-nix-fetchgit: remove pkgs.nix from the wrapper

We can assume that the user has Nix installed. Not having it in the
wrapper prevents pulling in a specific version of C++ Nix when the user
may prefer another version or Lix etc.

pkgs/development/haskell-modules/configuration-common.nix

@@ -1840,7 +1840,6 @@ with haskellLib;
       # PATH.
       deps = [
         pkgs.git
-        pkgs.nix
         pkgs.nix-prefetch-git
       ];
     in
@@ -1854,7 +1853,9 @@ with haskellLib;
           wrapProgram "$out/bin/update-nix-fetchgit" --prefix 'PATH' ':' "${lib.makeBinPath deps}"
         '';
       }))
-      (addTestToolDepends deps)
+      # pkgs.nix is not added to the wrapper since we can resonably expect it to be installed
+      # and we don't know which implementation the eventual user prefers
+      (addTestToolDepends (deps ++ [ pkgs.nix ]))
       # Patch for hnix compat.
       (appendPatches [
         (fetchpatch {