[TD] DrawViewPart.cpp: Fix a crash when user sets the PropertyVector Direction to zero.
[TD] DrawViewPart.cpp: Fix a crash when user sets the PropertyVector Direction to zero.

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master