Stop rebalance if progress = "none"

Sometimes couchbase reports that rebalance is running:

"rebalanceStatus":"running"

Although it's not actually progressing:

{"status":"none"}

This causes the operator to skip reconcile because it assumes rebalance is happening and will eventually finish when it won't:

time="2018-09-14T23:17:20Z" level=error msg="failed to reconcile: Skipping reconcile loop because the cluster is currently rebalancing" cluster-name=cb-example2 module=cluster