Fix a couple of clang compiler warnings:

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

src/Mod/TechDraw/Gui/QGMText.cpp

@@ -49,7 +49,7 @@ QGMText::QGMText() :
 
 QVariant QGMText::itemChange(GraphicsItemChange change, const QVariant &value)
 {
-    QPointF newPos(0.0,0.0);
+    //QPointF newPos(0.0,0.0);
     if(change == ItemPositionHasChanged && scene()) {
         Q_EMIT dragging();
     }