QPID-4787: HA brokers find self-address in brokers_url.

HA brokers need to know their own addresses, but it is not safe to simply use
local hosts name and Broker::getPort() since the broker may be listening on
multiple addresses. The solution is to have brokers check the ha-rokers-url for
their own address while doing the initial status check of the cluster.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1477165 13f79535-47bb-0310-9956-ffa450edef68