This PS updates the rabbitmq chart to make cluster formation
more robust, with the previous implementation it was possible
to form multiple descrete clusters within a single deployment
of the chart (eg if a network partition existed during formation)
Change-Id: Ie241d29230419ff829d9fbb22fa1a01275926903
Signed-off-by: Pete Birley <pete@port.direct>
b5e8c41d2e