Revert to old-style for-loop.

The containsInsideSubentity() method is defined on the iterator. Using a
range-based for-loop prevents us from calling it.

dune/fufem/functiontools/boundarydofs.hh

@@ -31,9 +31,9 @@ void constructBoundaryDofs(const BoundaryPatch<GridView>& boundaryPatch,
     boundaryDofs.unsetAll();
 
 
-    for (const auto& it : boundaryPatch) {
+    for (auto it = boundaryPatch.begin(); it != boundaryPatch.end(); ++it) {
 
-        const auto& inside = it.inside();
+        const auto& inside = it->inside();
         const auto& localCoefficients = basis.getLocalFiniteElement(inside).localCoefficients();
 
         for (size_t i=0; i<localCoefficients.size(); i++) {