grid managers: update the GridPart / GridView after loadBalance()

depending on the grid implementation, the grid view / grid part object
does not necessarily follow the change. For some reason, the grid part
still does not work in the parallel case (tested with dune-fem 2.4),
but that seems to be an issue on the dune-fem side.

ebos/eclcpgridmanager.hh

@@ -197,6 +197,8 @@ public:
 #endif
 
         cartesianIndexMapper_ = new CartesianIndexMapper(*grid_);
+
+        this->updateGridView_();
     }
 
     /*!