Multiple rebalances are required for CBAS replication to take effect.

Test case - 
test_cbas_node_crash_while_rebalancing_IN_cbas_nodes_does_not_change_actual_number_of_replicas
 
Steps to reproduce - 

1. Create 4 node cluster with 2 cbas and 2 KV nodes.
2. Set cbas replica to 3.
3. create cbas infra like datasets, dataverses and indexes.
4. Actual number of replica will be 1, as there are only 2 cbas nodes.
5. Now rebalance-In 2 more CBAS nodes.
6. while rebalance is happening, stop couchbase server on one of the existing cbas nodes.
7. rebalance fails as expected. Verify that no data loss happened on cbas side and the actual replica number is still 1.
8. start the couchbase server that was stopped in step 6.
9. rebalance again.
10. Once the rebalance completes, check the number of cbas replicas using analytics/cluster API, it shows as 1.
11. Rebalance one more time, now the actual number of replicas become 3.