multiply K_par with d in problem mmdg6

dune/mmdg/problems/mmdgproblem6.hh

@@ -95,7 +95,7 @@ public:
 
     for (int i = 0; i < dim; i++)
     {
-      permeability[i][i] = 1.0 * aperture(pos);//d_;
+      permeability[i][i] = 1.0 * aperture(pos);
     }
 
     return permeability;