Fix deployment steps for Redis Enterprise with HA templates

The migration procedure described at https://issues.jboss.org/browse/THREESCALE-2197?focusedCommentId=13716837&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13716837 only works to deploy system on Redis Enterprise if performed on top of a 3scale running instance that includes system-redis pod deployed. This is not the case of deployments using the HA templates.

We need to fix the Makefile, particularly the targets migrate-db, scale-down and scale-up to fit HA deployments:

• No system-redis DeploymentConfig
• Minimum of 2 replicas per pod