add pool name while register notification listener

oslo.messaging is exposing a new API allow creating listener by
supplying a pool name, then the listeners with that pool name will use
the queue name as the pool name, multiple listeners can be listening
with the same topic.

Change-Id: I220d50fad8cda6f6f50f31215a7a6b98523c35dc
Closes-Bug: #1388663
(cherry picked from commit c780569e8c3e5b5f13475059fdb7292d2d72e7bd)