do not catch polymorphic type by value
This silences a warning from GCC 8:
dune/geometry/virtualrefinement.cc:496:5: warning:
catching polymorphic type ‘class std::bad_cast’ by value [-Wcatch-value=]This silences a warning from GCC 8:
dune/geometry/virtualrefinement.cc:496:5: warning:
catching polymorphic type ‘class std::bad_cast’ by value [-Wcatch-value=]