Port replication configs are not set into rings

After if any of the replication port configuration options (object-server-port-rep, container-server-port-rep, account-server-port-rep) are changed, the ring files are not updated accordingly
so, when the service restarts, the replication fails with the message:

Can't find itself in policy with index 0 with ips 127.0.0.1, ::1, 10.5.0.41, fe80::f816:3eff:feaf:e114, 252.0.41.1, fe80::7c84:fbff:fe69:f2be, fe80::7c84:fbff:fe69:f2be, fe80::7098:6dff:fe95:2f72, fe80::1 and with port 6020 in ring file, not replicating

Steps to reproduce:

1. Install the swift cluster from charm version 272
2. Set any of the settings above with a value different than defaults
   juju config swift-storage-z1 object-server-port-rep=6020
3. Restart all swift-services in the nodes

Result:

- Changes are applied to object-server-replicator.conf but 'swift-ring-builder object.builder'
  show old information
- Swift logs show the error above
- Swift stop object/account and container replication