In method 'galerkinRestrict': allow coarse grid matrix to be of different type...

In method 'galerkinRestrict': allow coarse grid matrix to be of different type than fine grid matrix

With this simple patch I am able to abuse the method to compute certain
Schur complements.

dune/solvers/transferoperators/genericmultigridtransfer.hh

@@ -778,8 +778,8 @@ public:
 
 
 
-    template<class TransferOperatorType, class OperatorType>
-    static void galerkinRestrict(const TransferOperatorType& matrix, const OperatorType& fineMat, OperatorType& coarseMat)
+    template<class TransferOperatorType, class FineMatrixType, class CoarseMatrixType>
+    static void galerkinRestrict(const TransferOperatorType& matrix, const FineMatrixType& fineMat, CoarseMatrixType& coarseMat)
     {
         // ////////////////////////
         // Nonsymmetric case