Merge pull request #3584 from tianon/fix-docs-dockerfile

Fix docs Dockerfile to install correctly again

docs/Dockerfile

@@ -8,8 +8,8 @@ run apt-get update
 run apt-get install -y python-setuptools make
 run easy_install pip
 #from docs/requirements.txt, but here to increase cacheability
-run pip install Sphinx==1.1.3
-run pip install sphinxcontrib-httpdomain==1.1.9
+run pip install --no-use-wheel Sphinx==1.1.3
+run pip install --no-use-wheel sphinxcontrib-httpdomain==1.1.9
 add . /docs
 run cd /docs; make docs