title: Can't exclude subdirectory in python setup.py
body: <p>I have the following structure:</p>
  
  <pre><code>project
    - setup.py
    - app
      - stuff
      - to
      - include
      - module_to_exclude
        - more stuff
  </code></pre>
  
  <p>In <code>setup.py</code> I have:</p>
  
  <pre><code>setup(
      name="app",
      packages=find_packages(exclude=['module_to_exclude', '*.module_to_exclude', '*.module_to_exclude.*', 'module_to_exclude.*']),
      include_package_data=True,
      install_requires=[...],
      ext_modules=[],
      package_data={},
  )
  </code></pre>
  
  <p>But when I run:</p>
  
  <p><code>python setup.py bdist_wheel</code></p>
  
  <p>I can see that <code>module_to_exclude</code> is still being added. What am I doing wrong?</p>