installer: de-deplux activemq network connectors

Bug 1070747 - de-duplicate connectors on Network of ActiveMQ Brokers
https://bugzilla.redhat.com/show_bug.cgi?id=1070747

From docs bug:
https://bugzilla.redhat.com/show_bug.cgi?id=1066729
Procedure 7.20. To Configure a Network of ActiveMQ Brokers
Links to a broker configuration which uses duplex
NetworkConnectors. These duplex network connectors need only be
configured from the initiating broker, not on both sides of the
connection.
Merge pull request #314 from sosiouxme/duplex-ha-activemq-enterprise-2.1

installer: de-deplux activemq network connectors