ENH: flange: clean 0 directory.

tutorials/mesh/snappyHexMesh/flange/Allclean

@@ -4,6 +4,7 @@ cd ${0%/*} || exit 1    # run from this directory
 # Source tutorial clean functions
 . $WM_PROJECT_DIR/bin/tools/CleanFunctions
 
+rm -rf 0 > /dev/null 2>&1
 rm -f ./*.obj > /dev/null 2>&1
 rm -rf constant/extendedFeatureEdgeMesh > /dev/null 2>&1
 rm -f constant/triSurface/flange.eMesh > /dev/null 2>&1