OpenStack: Refresh documentation about ingress FIP

Since #3855, the installer is
able to attach the `ingressFloatingIP` specified in the
`install-config.yaml` to the ingress-port. Update the documentation to
reflect the change.

docs/user/openstack/README.md

@@ -322,9 +322,9 @@ If you have created the API DNS record, you should be able access the OpenShift
 
 ##### External Ingress (apps) Access
 
-The installer doesn't currently handle the Ingress floating IP address the same way it does the API one.
+In the same manner, you may have specified an Ingress floating IP by adding the `ingressFloatingIP` entry in your `install-config.yaml`, in which case the installer attaches the Floating IP address to the `ingress-port` automatically.
 
-To make the OpenShift Ingress access available (this includes logging into the deployed cluster), you will need to attach the Ingress floating IP to the `ingress-port` after the cluster is created.
+If not, you can always attach the Ingress floating IP to the `ingress-port` after the cluster is created.
 
 That can be done in the following steps: