Updating etcdcluster manifest does not upgrade the cluster unless the number of members is also changed

To reproduce:

1. Install etcd-operator 0.2
2. Create a 3-node etcdcluster with etcd image 3.6.8
3. Update etcdcluster.yaml to use image 3.6.10
4. `kubectl apply` the new manifest from `sample_autocert_etcdcluster.yaml`
5. etcdcluster definition is updated
6. The Statefulset does NOT get updated. No members actually get upgraded.
7. Try modifying etcdcluster-sample using `kubectl edit`
8. Statefulset still not updated
9. Edit the YAML file one more time, changing the number of members also
10. The statefulset will be updated, including the image version

It appears that changes made to the manifest for an existing cluster are not applied to the statefulset unless the user also changes the number of members. This is a missing logic loop somewhere.