Bug #7523: D1Client no longer updates stale NodeList
add nodelist refreshes to NodeLocator classes
Although we added Nodelist refreshing to D1Clients, it seems that at least the SettingsContextNodeLocator should also have the feature. Initial attempts to do this were frustrated by the inheritance hierarchy where the nodelist is set once at construction.
I think the solution is to use the setters in NodeLocator, and make sure there's consistency in NodeListNodeLocator and SettingsContextNodeLocator. The other approach would be to change the inheritance pattern so that SettingsContextNL inherits directly from NodeLocator.