DOC don't update setuptools

as recommended by ContinuumIO/anaconda-issues#542 (comment)

circle.yml

@@ -45,7 +45,7 @@ dependencies:
     # install numpy first as it is a compile time dependency for other packages
     - pip install --upgrade numpy
     # install documentation building dependencies
-    - pip install --upgrade matplotlib setuptools nose coverage sphinx pillow sphinx-gallery sphinx_bootstrap_theme cython numpydoc
+    - pip install --upgrade matplotlib nose coverage sphinx pillow sphinx-gallery sphinx_bootstrap_theme cython numpydoc
     # Installing required packages for `make -C doc check command` to work.
     - sudo -E apt-get -yq update
     - sudo -E apt-get -yq --no-install-suggests --no-install-recommends --force-yes install dvipng texlive-latex-base texlive-latex-extra