Fix NRE in Actor.ProcessMessage when interacting with traceInbox and there is no savedReq reference (instead of writing empty tags in this case, I thought it was better to write no tag at all if that data is not available)
Fix NRE in Actor.ProcessMessage when interacting with traceInbox and there is no savedReq reference (instead of writing empty tags in this case, I thought it was better to write no tag at all if that data is not available)

louthy/echo-process,louthy/echo-process