ISPN-2773 Can't access a non-clustered cache via HotRod

https://issues.jboss.org/browse/ISPN-2773

Check for a null RpcManager in AbstraceEncoder1x.getTopologyResponse.

I also included a fix for https://issues.jboss.org/browse/ISPN-2774 - it cuts down the running time of the HotRod client test suite from 190 seconds to 35 seconds.