Interceptor's destroy method is never called.

One possible way to fix this would be to :-

* When FilterDispatcher destroy itself (its destroy() method)
* It calls DispatcherUtil's cleanup() method
* which could call ConfigurationManager.destroyConfiguration()
* we could add the code to destroy the interceptor there.

The idea is to get the RuntimeConfiguration, and then get the actionConfigs which is
Map<String, Map<String, ActionConfig>>
The first String is the namespace, while the second String is the action name, With ActionConfig we could get a list of ActionMapping which holds an instance of Interceptor object. We could then invoke destroy() method on it.

thoughts?