19537 - update setup documentation for the rabbitmq connector

This patch updates the command syntax for the current (since November
2012) version of rabbitmqadmin.

It also adds a specific admin user to the rabbitmq instance to
create the exchanges with as guest/guest cannot as it's
in a new vhost.

Combines/closes github Pull Requests #68 and #100
Merge pull request #120 from richardc/bug/master/19537

19537 - update setup documentation for the rabbitmq connector