a11y: allow navigation on non reactive items

At this moment non-reactive items are being used in
several cases as non-sensitive, but they still
require keyboard navigation.

https://bugzilla.gnome.org/show_bug.cgi?id=667439

src/st/st-widget.c

@@ -1892,8 +1892,7 @@ st_widget_real_navigate_focus (StWidget         *widget,
   while (focus_child && clutter_actor_get_parent (focus_child) != widget_actor)
     focus_child = clutter_actor_get_parent (focus_child);
 
-  if (clutter_actor_get_reactive (widget_actor) &&
-      widget->priv->can_focus)
+  if (widget->priv->can_focus)
     {
       if (!focus_child)
         {