acu93479 - Change agent to route response to request.reply_to so that ma...

...pper in control
@ryanwilliamson @tony-spataro-rs 
This change puts control back into the mapper for where an agent sends its responses. This  will help reduce the number of message hops when the router (aka broker proxy is introduced). I verified this works by rebooting a 5.8 instance after inserting these modifications. I would like to get this change into 5.9.

BTW, the change I submitted Saturday morning had acu number messed up. That is why I am resubmitting.