BUG: In ctkVTKRenderView, fix function activeCamera()

The active camera was returned if IsActiveCameraCreated was false,
the logic is now reversed !

Libs/Visualization/VTK/Widgets/ctkVTKRenderView.cpp

@@ -174,11 +174,11 @@ vtkCamera* ctkVTKRenderView::activeCamera()
   CTK_D(ctkVTKRenderView);
   if (d->Renderer->IsActiveCameraCreated())
     {
-    return 0;
+    return d->Renderer->GetActiveCamera();
     }
   else
     {
-    return d->Renderer->GetActiveCamera();
+    return 0;
     }
 }