Make mmgtest independent of IpOpt

dune/solvers/test/CMakeLists.txt

 set(GRID_BASED_TESTS
   cgsteptest
   gssteptest
+  mmgtest
   multigridtest
   projectedgradienttest
   obstacletnnmgtest
@@ -13,7 +14,7 @@ set(OTHER_TESTS
   sumoperatortest
   )
 
-set(TESTS_IPOPT mmgtest quadraticipoptsolvertest)
+set(TESTS_IPOPT quadraticipoptsolvertest)
 
 if(HAVE_IPOPT)
   list(APPEND GRID_BASED_TESTS ${TESTS_IPOPT})

dune/solvers/test/mmgtest.cc

@@ -21,7 +21,6 @@
 // dune-solver includes
 #include <dune/solvers/norms/energynorm.hh>
 #include <dune/solvers/iterationsteps/mmgstep.hh>
-#include <dune/solvers/solvers/quadraticipopt.hh>
 #include <dune/solvers/transferoperators/mandelobsrestrictor.hh>
 #include <dune/solvers/transferoperators/truncatedcompressedmgtransfer.hh>
 
@@ -34,7 +33,6 @@ void solveObstacleProblemByMMGSolver(const GridType& grid, const MatrixType& mat
     typedef VectorType Vector;
     typedef MatrixType Matrix;
     typedef EnergyNorm<Matrix, Vector> Norm;
-    typedef QuadraticIPOptSolver<MatrixType,VectorType> Solver;
 
     // create double obstacle constraints
     const int blockSize = VectorType::block_type::dimension;