minor change: take the matrix plugged into the SumOperator to compare N(),...

minor change: take the matrix plugged into the SumOperator to compare N(), instead of the member of the SumOperator

[[Imported from SVN: r5944]]

dune/solvers/test/sumoperatortest.cc

@@ -150,12 +150,12 @@ bool check()
 
 
     /* test for consistency of return value of N() */
-    if (sum_op.N() != sum_op.sparseMatrix().N())
+    if (sum_op.N() != sparse_matrix.N())
     {
         std::cout << "SumOperator::N does not return correct value for the SumOperator constructed from given matrices. (returns " << sum_op.N() << ", should return " << sum_op.sparseMatrix().N() << ")" << std::endl;
         passed = false;
     }
-    if (sum_op_default.N() != sum_op_default.sparseMatrix().N())
+    if (sum_op_default.N() !=sparse_matrix.N())
     {
         std::cout << "SumOperator::N does not return correct value for the default-constructed SumOperator." << std::endl;
         passed = false;