pythonPackages.azure*: use pythonNamespaces

pkgs/development/python-modules/azure-mgmt-dns/default.nix

@@ -27,10 +27,7 @@ buildPythonPackage rec {
   ];
 
   # this is still needed for when the version is overrided
-  # to previous versions. E.g azure-cli
-  postInstall = lib.optionalString isPy3k ''
-    rm -f $out/${python.sitePackages}/azure/{,mgmt/}__init__.py
-  '';
+  pythonNamespaces = [ "azure.mgmt" ];
 
   # has no tests
   doCheck = false;