Fix a couple of clang compiler warnings:

-Wunused-variable
-Winconsistent-missing-override
-Wdelete-non-virtual-dtor
-Wunused-private-field
-Wformat

src/Mod/TechDraw/App/DrawViewPart.cpp

@@ -118,8 +118,7 @@ using namespace std;
 PROPERTY_SOURCE(TechDraw::DrawViewPart, TechDraw::DrawView)
 
 DrawViewPart::DrawViewPart(void) : 
-    geometryObject(0),
-    on1(true)
+    geometryObject(0)
 {
     static const char *group = "Projection";
     static const char *sgroup = "HLR Parameters";