Disable auto discovery

setuptools 61.0 brings breaking changes which are not backwork
compatible, details in related bug and [1].

Users that don't set ``packages``, ``py_modules``, or `configuration`
are still likely to observe the auto-discovery behavior, which may
halt the build if the project contains multiple directories and/or
multiple Python files directly under the project root.

To disable auto discovery, one can do below in setup.py

~~~
setuptools.setup(..,packages=[],..)
~~~

or

~~~
setuptools.setup(..,py_modules=[],..)
~~~

[1] https://github.com/pypa/setuptools/issues/3197

Releated-Bug: #1966382
Change-Id: I0c9e9833bc30726d575f2560bd0a252417168f8a

setup.py

@@ -16,4 +16,5 @@ import setuptools
 
 setuptools.setup(
     setup_requires=['pbr'],
+    py_modules=[],
     pbr=True)