fvAgglomerationMethods/Allwmake: Better check for the availability of

libMGridGen

src/fvAgglomerationMethods/Allwmake

@@ -5,7 +5,7 @@ set -x
 
 export ParMGridGen=$WM_THIRD_PARTY_DIR/ParMGridGen-1.0
 
-if [ -d "$ParMGridGen/MGridGen/Lib" ]
+if [ -e "$FOAM_LIBBIN/libMGridGen.so" ]
 then
     wmake $makeType MGridGenGamgAgglomeration
 fi