Remove directory contents if it exists

src/freedombone-app-matrix

     if [ ! -d $INSTALL_DIR/matrix ]; then
         mkdir -p $INSTALL_DIR/matrix
     fi
+    rm -rf /usr/local/lib/python2.7/dist-packages/ldap*
+    if [ -d $INSTALL_DIR/matrix ]; then
+        rm -rf $INSTALL_DIR/matrix/*
+    fi
     pip install --upgrade --process-dependency-links . -b $INSTALL_DIR/matrix
     if [ ! "$?" = "0" ]; then
         echo $'Failed to install matrix home server'