Occasionally rabbitmq replicas fail to come up when running in
zuul due to resource constraints. This causes random failures
and needless rechecks when it comes up.
This change sets the number of replicas when deploying the compute
kit script to 1 from the default 2.
Change-Id: Icdcc075a88d05f87a7f787d306d6b430485964c9
ba0b7eeb05