wayland: Scale unconstrained rect changing monitor scale

When a window is moved across monitors with different scales, its
rectangle is scaled accordingly. We also need to scale the
unconstrained_rect rectangle, so that moving a window via
meta_window_move_resize() which uses the unconstrained_rect.

https://bugzilla.gnome.org/show_bug.cgi?id=755097

src/wayland/meta-window-wayland.c

@@ -361,6 +361,7 @@ meta_window_wayland_main_monitor_changed (MetaWindow *window,
 
   /* Window size. */
   scale_rect_size (&window->rect, scale_factor);
+  scale_rect_size (&window->unconstrained_rect, scale_factor);
 
   /* Window geometry offset (XXX: Need a better place, see
    * meta_window_wayland_move_resize). */