DOC/CI: ensure correct pandas version (GH15311)

Author: jorisvandenbossche

ci/build_docs.sh

@@ -22,9 +22,6 @@ if [ x"$DOC_BUILD" != x"" ]; then
     echo "Will build docs"
 
     source activate pandas
-    conda install -n pandas -c r r rpy2 --yes
-
-    time sudo apt-get $APT_ARGS install dvipng texlive-latex-base texlive-latex-extra
 
     mv "$TRAVIS_BUILD_DIR"/doc /tmp
     cd /tmp/doc

ci/requirements-3.5_DOC_BUILD.sh

@@ -5,3 +5,7 @@ source activate pandas
 echo "install DOC_BUILD"
 
 conda install -n pandas -c conda-forge feather-format
+
+conda install -n pandas -c r r rpy2 --yes
+
+time sudo apt-get $APT_ARGS install dvipng texlive-latex-base texlive-latex-extra