Move pandas/dumpy upstream install to be the last pkg install operation

pandas and numpy were getting reinstalled by conda after the
force uninstall here.

continuous_integration/travis/install.sh

@@ -53,13 +53,6 @@ conda install -q -c conda-forge \
     sqlalchemy \
     toolz
 
-if [[ ${UPSTREAM_DEV} ]]; then
-    echo "Installing NumPy and Pandas dev"
-    conda uninstall -y --force numpy pandas
-    PRE_WHEELS="https://7933911d6844c6c53a7d-47bd50c35cd79bd838daf386af554a83.ssl.cf2.rackcdn.com"
-    pip install -q --pre --no-deps --upgrade --timeout=60 -f $PRE_WHEELS numpy pandas
-fi;
-
 # install pytables from defaults for now
 conda install -q pytables
 
@@ -92,6 +85,13 @@ pip install -q --upgrade \
     pytest-xdist \
     xxhash
 
+if [[ ${UPSTREAM_DEV} ]]; then
+    echo "Installing NumPy and Pandas dev"
+    conda uninstall -y --force numpy pandas
+    PRE_WHEELS="https://7933911d6844c6c53a7d-47bd50c35cd79bd838daf386af554a83.ssl.cf2.rackcdn.com"
+    pip install -q --pre --no-deps --upgrade --timeout=60 -f $PRE_WHEELS numpy pandas
+fi;
+
 # Install dask
 pip install -q --no-deps -e .[complete]
 echo conda list