Also remove mysterious hack from pkg_resources.extern

pkg_resources/extern/__init__.py

@@ -43,13 +43,6 @@ class VendorImporter:
                 __import__(extant)
                 mod = sys.modules[extant]
                 sys.modules[fullname] = mod
-                # mysterious hack:
-                # Remove the reference to the extant package/module
-                # on later Python versions to cause relative imports
-                # in the vendor package to resolve the same modules
-                # as those going through this importer.
-                if prefix and sys.version_info > (3, 3):
-                    del sys.modules[extant]
                 return mod
             except ImportError:
                 pass