ISPN-4920 CancelledKeyException when reading event means channel closed

https://issues.jboss.org/browse/ISPN-4920
I don't think this is the correct spot, it seems the exception never makes it up this high as it is caught at https://github.com/galderz/infinispan/blob/t_4920/client/hotrod-client/src/main/java/org/infinispan/client/hotrod/event/ClientListenerNotifier.java#L243