Fix a small bug I noticed while working on something else. app_queue did not

unregister its device state monitoring callback in unload_module().  So, this
would make Asterisk crash on the first device state change after you 
unload the module.


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@64868 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_queue.c

@@ -4469,6 +4469,7 @@ static int unload_module(void)
 	res |= ast_custom_function_unregister(&queuemembercount_function);
 	res |= ast_custom_function_unregister(&queuememberlist_function);
 	res |= ast_custom_function_unregister(&queuewaitingcount_function);
+	ast_devstate_del(statechange_queue, NULL);
 
 	ast_module_user_hangup_all();