fixed small bug

git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@5845 2fb0f335-1f38-0410-981e-8018bf24f1b0

appl/lecture/mhs/groundwater/external_interface.hh

@@ -62,7 +62,8 @@ public:
     //Initialization of ISP Parameters
     {
         using namespace std;
-        double viscosity, density;
+        double viscosity=0.001;
+        double density=1000;
 
         std::cout << std::endl
                 << "-----> ISP: Interface Soil Properties Initialization ...\n";