Actually use use_whey parameter for test_make_setup_cfg_existing

tests/test_files/test_packaging_/test_make_setup_cfg_existing_False_.cfg

@@ -6,6 +6,42 @@
 #     * mypy
 #     * options.entry_points
 
+[metadata]
+name = hello-world
+version = 1.2.3
+author = Joe Bloggs
+author_email = j.bloggs@example.com
+license = MIT License
+keywords = awesome, python, project
+long_description = file: README.rst
+long_description_content_type = text/x-rst
+platforms = Windows
+url = https://github.com/octocat/hello-world
+project_urls =
+    Documentation = https://hello-world.readthedocs.io/en/latest
+    Issue Tracker = https://github.com/octocat/hello-world/issues
+    Source Code = https://github.com/octocat/hello-world
+classifiers =
+    License :: OSI Approved :: MIT License
+    Operating System :: Microsoft :: Windows
+    Programming Language :: Python
+    Programming Language :: Python :: 3 :: Only
+    Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
+    Programming Language :: Python :: Implementation :: CPython
+
+[options]
+python_requires = >=3.6.1
+zip_safe = False
+include_package_data = True
+packages = find:
+
+[options.packages.find]
+exclude =
+    doc-source
+    tests
+    tests.*
+
 [somesection]
 key=value
 apple=fruit