title: Why find_packages(exclude=xxx) does not work when doing setup.py sdist?
body: <p>I am packaging my source code, but I do not want to include tests and docs because it will be too big.</p>
  
  <p>To do that I include in my setup.py:</p>
  
  <pre><code>setup(...
        packages=find_packages(exclude=['tests.*','tests','docs.*','docs']),
        ...
  )
  </code></pre>
  
  <p>When doing a </p>
  
  <pre><code>python setup.py sdist
  </code></pre>
  
  <p>I can see that my root tests/ and docs/ dirs and everything inside are still included in the generated distribution.</p>
  
  <p>It seems that only</p>
  
  <pre><code>python setup.py bdist
  </code></pre>
  
  <p>is sensible to the exclude parameter.</p>
  
  <p>Why ? is it possible to exclude dirs for 'setup.py sdist' ?</p>