Double requirement given when trying to use pip install pandas : <p>I want to build a Docker container using a Dockerfile containing <code>pip install -r requirements.txt</code>. pandas==0.22.0 is included in this requirements.txt file. Untill two days ago, the Docker container was perfectly build. Starting from yesterday, I receive an error:</p>

<blockquote>
  <p>Double requirement given: numpy==1.12.1 from
  <a href="https://pypi.python.org/packages/02/64/c6c1c24ff4dbcd789fcfdb782e343ac23c074f6b8b03e818ff60eb0f937f/numpy-1.12.1-cp34-cp34m-manylinux1_x86_64.whl#md5=6288d4e9cfea859e03dc82879539d029" rel="noreferrer">https://pypi.python.org/packages/02/64/c6c1c24ff4dbcd789fcfdb782e343ac23c074f6b8b03e818ff60eb0f937f/numpy-1.12.1-cp34-cp34m-manylinux1_x86_64.whl#md5=6288d4e9cfea859e03dc82879539d029</a> (already in numpy==1.9.3 from
  <a href="https://pypi.python.org/packages/fc/1b/a1717502572587c724858862fd9b98a66105f3a3443225bda9a1bd16ee14/numpy-1.9.3-cp34-cp34m-manylinux1_x86_64.whl#md5=e1130c8f540a759d79ba5e8960f6915a" rel="noreferrer">https://pypi.python.org/packages/fc/1b/a1717502572587c724858862fd9b98a66105f3a3443225bda9a1bd16ee14/numpy-1.9.3-cp34-cp34m-manylinux1_x86_64.whl#md5=e1130c8f540a759d79ba5e8960f6915a</a>,
  name='numpy')</p>
</blockquote>

<p>This error occurs both on Mac (Docker version: 18.03.0-ce-mac58 (23607)) and Ubuntu 16.04.3 (Docker version:  17.12.0-ce, build c97c6d6).</p>

<p>I already tried to use different versions op pandas, to preinstall numpy, to remove pands from the requirements.txt file and install it seperately. As well as trying to install with <code>apt-get install python-pandas</code>. For the latter solution pandas v14 was installed, while I need at least v19.</p>
