made mimetic stuff work again, thank you, Andreas!

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@6503 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/decoupled/2p/diffusion/mimetic/mimeticpressure2p.hh

@@ -150,6 +150,7 @@ public:
     void initialize(bool solveTwice = true)
     {
         updateMaterialLaws();
+        pressTrace_ = 0; f_ = 0;
         assemble(true);
         solve();
         postprocess();
@@ -239,7 +240,7 @@ void MimeticPressure2P<TypeTag>::solve()
     std::cout << "MimeticPressure2P: solve for pressure" << std::endl;
 
     Solver solver(problem_);
-    solver.solve(*A_, problem_.variables().pressure(), f_);
+    solver.solve(*A_, pressTrace_, f_);
     return;
 }