[mpfa][localindexset] do not use small local index type

On 3d grids, the maximum value of 8-bit integer types can easily be
surpassed for the local indices within interaction volumes. We use the
larger local index type now. This way we should always be on the safe
side.

dumux/discretization/cellcentered/mpfa/dualgridindexset.hh

@@ -45,7 +45,7 @@ struct NodalIndexSetDefaultTraits
 {
     using GridView = GV;
     using GridIndexType = typename IndexTraits<GV>::GridIndex;
-    using LocalIndexType = typename IndexTraits<GV>::SmallLocalIndex;
+    using LocalIndexType = typename IndexTraits<GV>::LocalIndex;
 
     //! per default, we use dynamic data containers (iv size unknown)
     template< class T > using NodalScvDataStorage = std::vector< T >;