etc/config.sh/metis: Updated for changes to ThirdParty-dev/Allwmake

See commit b627924a4bf104521b567d3aa3dc80c864325b1a

    Allwmake: Added scripted changes for REALTYPEWIDTH and IDXTYPEWIDTH
    Patch contributed by Bruno Santos
    Resolves bug-report http://bugs.openfoam.org/view.php?id=2085

etc/config.sh/metis

@@ -34,6 +34,6 @@
 #------------------------------------------------------------------------------
 
 export METIS_VERSION=metis-5.1.0
-export METIS_ARCH_PATH=$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER/$METIS_VERSION
+export METIS_ARCH_PATH=$WM_THIRD_PARTY_DIR/platforms/$WM_ARCH$WM_COMPILER$WM_LABEL_OPTION/$METIS_VERSION
 
 #------------------------------------------------------------------------------