Do not hand obstacles to MMGStep as raw pointers

MMGStep wants shared pointers or values nowadays.

dune/elasticity/common/trustregionsolver.cc

@@ -192,7 +192,7 @@ setup(const typename BasisType::GridView::Grid& grid,
     // //////////////////////////////////////////////////////////
 
     hasObstacle_.resize(basis.size(), true);
-    mmgStep->setHasObstacles(&hasObstacle_);
+    mmgStep->setHasObstacles(hasObstacle_);
 
 }
 
@@ -274,7 +274,7 @@ void TrustRegionSolver<BasisType,VectorType>::solve()
         mgStep->setProblem(stiffnessMatrix, corr, rhs);
 
         trustRegionObstacles = trustRegion.obstacles();
-        mgStep->setObstacles(&trustRegionObstacles);
+        mgStep->setObstacles(trustRegionObstacles);
 
         innerSolver_->preprocess();