netbox: Inherit gunicorn from the package

I was using a 23.11 package on a NixOS 23.05 system and this caused the
python that was used in gunicorn to differ from the python the postgres
lib was linked against.

nixos/modules/services/web-apps/netbox.nix

@@ -317,7 +317,7 @@ in {
 
         serviceConfig = defaultServiceConfig // {
           ExecStart = ''
-            ${pkgs.python3Packages.gunicorn}/bin/gunicorn netbox.wsgi \
+            ${pkg.gunicorn}/bin/gunicorn netbox.wsgi \
               --bind ${cfg.listenAddress}:${toString cfg.port} \
               --pythonpath ${pkg}/opt/netbox/netbox
           '';

pkgs/servers/web-apps/netbox/generic.nix

@@ -1,6 +1,5 @@
 { lib
 , fetchFromGitHub
-, fetchpatch
 , python3
 , version
 , hash
@@ -94,6 +93,7 @@
       passthru = {
         # PYTHONPATH of all dependencies used by the package
         pythonPath = python3.pkgs.makePythonPath propagatedBuildInputs;
+        gunicorn = python3.pkgs.gunicorn;
         inherit tests;
       };