Use 'pip uninstall', to handle the failure of --upgrade

install/53_pymsc.sh

@@ -2,7 +2,23 @@
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 . ${DIR}/common.sh
 
+# Setup pymsc in ~/.local
 cd $DIR/../pymsc || exit 1
+
+# Skip install if the version installed is the same and the tree is clean
+HEAD="$(grep __version msccore/__init__.py | awk '{print $NF}')"
+
+VERSION_INSTALLED="$(pip2 freeze | grep taste-msc | awk -F= '{print $NF}')"
+git status >/dev/null
+TREE_CLEAN=$?
+if [ ${TREE_CLEAN} -eq 0 -a "${HEAD}" == "${VERSION_INSTALLED}" ] ; then
+    echo taste-msc tree is clean and already installed. Skipping taste-msc install...
+    exit 0
+fi
+
+# Unfortunately, the --upgrade DOES NOT ALWAYS WORK.
+# Uninstall first...
+echo y | pip2 uninstall taste-msc
 pip2 install --user --upgrade . || exit 1
 
 # Add .local/bin to PATH