Fix shutdown crash with primitives in the document

and cleanup the header

src/Mod/PartDesign/Gui/ViewProviderDatumCS.cpp

@@ -83,7 +83,6 @@ void ViewProviderDatumCoordinateSystem::attach ( App::DocumentObject *obj ) {
     getShapeRoot ()->addChild(binding);
     getShapeRoot ()->addChild(material);
 
-    coord = new SoCoordinate3();
     coord->point.setNum(4);
 
     ViewProviderDatum::setExtents ( defaultBoundBox () );

src/Mod/PartDesign/Gui/ViewProviderPrimitive.h

@@ -52,10 +52,7 @@ protected:
     void updateAddSubShapeIndicator();
     
     std::string                 displayMode;
-    SoSeparator*                previewShape;
     PartGui::SoBrepFaceSet*     previewFaceSet;
-    SoCoordinate3*              previewCoords;
-    SoNormal*                   previewNorm;
 };
 
 } // namespace PartDesignGui