Take morph from our nixpkgs

nixpkgs.json

 { "name": "nixpkgs"
-, "url": "https://github.com/PrivateStorageio/nixpkgs/archive/d1eecb8286a01aeaa07e78fdc6f4c5e2ba638629.tar.gz"
-, "sha256": "11h2w6aplyb50lsvdyzw6y6whbfqlsmyr6s3f8a8915142i9wh3b"
+, "url": "https://github.com/PrivateStorageio/nixpkgs/archive/31c7a57bd9972979275fbfd9e490bfb502154c11.tar.gz"
+, "sha256": "0chvfxi2xcqhnabivjych8xdz7lm9svkvribjssyyaxc54xpql24"
 }

shell.nix

@@ -4,19 +4,9 @@ let
   nixpkgs = import nixpkgs-src { };
 in
 { pkgs ? nixpkgs }:
-let
-  # Get a version of Morph known to work with our version of NixOS.
-  morph-src = pkgs.fetchFromGitHub {
-    owner = "DBCDK";
-    repo = "morph";
-    rev = "3856a9c2f733192dee1600b8655715d760ba1803";
-    hash = "sha256:0jhypvj45yjg4cn4rvb2j9091pl6z5j541vcfaln5sb3ds14fkwf";
-  };
-  morph = pkgs.callPackage (morph-src + "/nix-packaging") { };
-in
 pkgs.mkShell {
   NIX_PATH = "nixpkgs=${nixpkgs.path}";
   buildInputs = [
-    morph
+    pkgs.morph
   ];
 }