refactor(SLandmarksAdaptor): improved landmarks deselection

The point is deselected on right click. Depending on the scene (images or meshes),
we received PressEvent or ReleaseEvent.

Bundles/LeafVisu/visuVTKAdaptor/src/visuVTKAdaptor/SLandmarks.cpp

@@ -269,7 +269,7 @@ void SLandmarks::doStart() throw(fwTools::Failed)
     vtkDeselectLandmarksCallBack* callback = vtkDeselectLandmarksCallBack::New();
     callback->setAdaptor(this->getSptr());
     m_noSelectionCommand = callback;
-    this->getInteractor()->AddObserver(vtkCommand::LeftButtonPressEvent, m_noSelectionCommand);
+    this->getInteractor()->AddObserver(vtkCommand::RightButtonPressEvent, m_noSelectionCommand);
     this->getInteractor()->AddObserver(vtkCommand::RightButtonReleaseEvent, m_noSelectionCommand);
 
     this->doUpdate();