plugins/routing/activemq: Take array of hosts

In the ActiveMQ routing plug-in, interpret ACTIVEMQ_HOST as
a comma-separated list of host:port pairs, and use this list of hosts when
connecting to ActiveMQ for redundancy.

This commit fixes bug 1102432.
Merge pull request #5460 from Miciah/bug-1102432-plugins-routing-activemq-take-array-of-hosts

Merged by openshift-bot