Prevent Loop in BRepBuilderAPI_Transform

- if a scale transform with scale = 0 is passed to
  BRepBuilderAPI_Transform, it will loop forever.
  If Page.keepUpdated is false, and Views have not yet
  been executed (ex at load time), Views will have a
  0.0 x 0.0 bbox and if Autoscale is true, a scale of
  0.0 will be used in fit-to-page.

src/Mod/TechDraw/App/DrawView.cpp

@@ -249,6 +249,10 @@ void DrawView::setPosition(double x, double y)
 double DrawView::getScale(void) const
 {
     auto result = Scale.getValue();
+    if (!(result > 0.0)) {
+        result = 1.0;
+        Base::Console().Log("DrawView - %s - bad scale found (%.3f) using 1.0\n",getNameInDocument(),Scale.getValue());
+    }
     return result;
 }