python2Packages: remove superfluous overrides

Since Python 2 is not supported anymore we only keep those overrides
which are used by leaf packages.

pkgs/development/python-modules/importlib-resources/2.nix

@@ -1,38 +0,0 @@
-{ lib
-, buildPythonPackage
-, fetchPypi
-, setuptools-scm
-, importlib-metadata
-, typing
-, singledispatch
-, python
-}:
-
-buildPythonPackage rec {
-  pname = "importlib-resources";
-  version = "3.3.1";
-
-  src = fetchPypi {
-    pname = "importlib_resources";
-    inherit version;
-    sha256 = "0ed250dbd291947d1a298e89f39afcc477d5a6624770503034b72588601bcc05";
-  };
-
-  nativeBuildInputs = [ setuptools-scm ];
-  propagatedBuildInputs = [
-    importlib-metadata
-    singledispatch
-    typing
-  ];
-
-  checkPhase = ''
-    ${python.interpreter} -m unittest discover
-  '';
-
-  meta = with lib; {
-    description = "Read resources from Python packages";
-    homepage = "https://importlib-resources.readthedocs.io/";
-    license = licenses.asl20;
-    maintainers = [ ];
-  };
-}

pkgs/development/python-modules/importlib-resources/default.nix

@@ -1,10 +1,10 @@
 { lib
+, isPy27
 , buildPythonPackage
 , fetchPypi
 , setuptools-scm
 , importlib-metadata
 , typing ? null
-, singledispatch ? null
 , pythonOlder
 , python
 }:
@@ -12,6 +12,7 @@
 buildPythonPackage rec {
   pname = "importlib-resources";
   version = "5.4.0";
+  disabled = isPy27;
 
   src = fetchPypi {
     pname = "importlib_resources";
@@ -25,8 +26,6 @@ buildPythonPackage rec {
 
   propagatedBuildInputs = [
     importlib-metadata
-  ] ++ lib.optional (pythonOlder "3.4") [
-    singledispatch
   ] ++ lib.optional (pythonOlder "3.5") [
     typing
   ];