box models: make them work again for EnablePartialReassemble == false

oops. small mistake

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@6638 2fb0f335-1f38-0410-981e-8018bf24f1b0

dumux/boxmodels/common/boxassembler.hh

@@ -313,6 +313,9 @@ public:
      */
     void markVertexRed(int globalVertIdx)
     {
+        if (!enablePartialReassemble_)
+            return;
+
         vertexColor_[globalVertIdx] = Red;
     }