Avoid moving and resizing override-redirect windows

Override-redirect windows should not be moved or resized by the
window manager.

- Mark override-redirect windows as already placed to avoid
  placing them when first shown.
- Don't move-resize newly created override-redirect MetaWindow
- Don't queue a resize on override-redirect windows when reading
  their WM_TRANSIENT_FOR hint.
- Add g_return_if_fail (!window->override_redirect) to catch
  unexpected code paths that might result in override-redirect
  windows being moved or resized.

http://bugzilla.gnome.org/show_bug.cgi?id=582639

src/core/window-props.c

@@ -1446,7 +1446,7 @@ reload_transient_for (MetaWindow    *window,
       window->xtransient_for != window->xgroup_leader)
     meta_window_group_leader_changed (window);
 
-  if (!window->constructing)
+  if (!window->constructing && !window->override_redirect)
     meta_window_queue (window, META_QUEUE_MOVE_RESIZE);
 }