python3Packages.ncclient: cleanup, fix hash (#443164)

pkgs/development/python-modules/dynaconf/default.nix

···
     versionCheckHook
   ];
 
+  disabledTests = [
+    # AssertionError: assert 42.1 == 'From development env'
+    "test_envless_load_file"
+  ];
+
   disabledTestPaths = [
     # import file mismatch
     # imported module 'app_test' has this __file__ attribute:

pkgs/development/python-modules/ncclient/default.nix

···
   paramiko,
   setuptools,
   pytestCheckHook,
-  pythonOlder,
 }:
 
 buildPythonPackage rec {
···
   version = "0.7.0";
   pyproject = true;
 
-  disabled = pythonOlder "3.7";
-
   src = fetchFromGitHub {
     owner = "ncclient";
     repo = "ncclient";
     tag = "v${version}";
-    hash = "sha256-GSa7UkBwbwggFqwNFTg2KNqGV5412EE41ma/dzPIEuU=";
+    # Upstream uses .gitattributes to inject information about the revision
+    # hash and the refname into `ncclient/_version.py`, see:
+    #
+    # - https://git-scm.com/docs/gitattributes#_export_subst and
+    # - https://github.com/ncclient/ncclient/blob/e056e38af2843de0608da58e2f4662465c96d587/ncclient/_version.py#L25-L28
+    postFetch = ''
+      sed -i 's/git_refnames = "[^"]*"/git_refnames = " (tag: ${src.tag})"/' $out/ncclient/_version.py
+    '';
+    hash = "sha256-vSX+9nTl4r6vnP/vmavdmdChzOC8P2G093/DQNMQwS4=";
   };
 
   build-system = [
···
 
   pythonImportsCheck = [ "ncclient" ];
 
-  meta = with lib; {
+  meta = {
     description = "Python library for NETCONF clients";
     homepage = "https://github.com/ncclient/ncclient";
     changelog = "https://github.com/ncclient/ncclient/releases/tag/${src.tag}";
-    license = licenses.asl20;
-    maintainers = with maintainers; [ xnaveira ];
+    license = lib.licenses.asl20;
+    maintainers = with lib.maintainers; [ xnaveira ];
   };
 }