title: pip install succeeded, but setup install failed
body: <p>I used <code>pip install -r pip_list.txt</code> successfully.</p>
  <pre class="lang-py prettyprint-override"><code># setup.py
  from setuptools import setup
  
  setup(
      name='test',
      version='0.1',
      py_modules=['test'],
      install_requires=[
        ...  # Same as pip_list.txt
      ],
      entry_points='''
          [console_scripts]
          test=test:cli
      ''',
  )
  </code></pre>
  <p>run <code>python setup.py install</code> failed.<br />
  <code>error: idna 3.1 is installed but idna&lt;3,&gt;=2.5 is required by {'requests'}</code></p>
  <p>pip.conf</p>
  <pre><code>[global] 
  index_url = https://.../prod/+simple/ 
  [search] 
  index = https://.../prod/
  </code></pre>
  <p>setup.cfg</p>
  <pre><code>[easy_install]
  index_url = https://.../prod/+simple/ 
  </code></pre>
  <p><strong>I did not find the [search] option in setup.cfg</strong>.Is the above error related to this?</p>