ISPN-4882 Fix HotRod authentication with clustered containers

ISPN-4882 Fix HotRod authentication with clustered containers bywrapping calls to RpcManager and DistributionManager in security actions

https://issues.jboss.org/browse/ISPN-4882
(only now I noticed this change)
why this is the only place where you check if the ```subject``` is ```null``` (compared with ```DECODE_KEY```, etc...)?