Remove instructions for restarting RabbitMQ

Per Vladimir, this is no longer required or accurate
since we reimplemented RabbitMQ HA cluster reassembling mechanism.

Also removed links to this section in Release Notes
and terminology/rabbitmq

Change-Id: I0a6b1bbcbf64d537f1e7c70c17771598e9d1b3d3
Merge "Remove instructions for restarting RabbitMQ"