Octavia healthmonitors cannot be created as PING in Red Hat OpenStack Platform 13

Issue

Octavia healthmonitors cannot be created as PING in Red Hat OpenStack Platform 13

The following sequence is invalid:

openstack loadbalancer create --name lb1 --vip-subnet-id private-subnet
openstack loadbalancer listener create --name listener1 --protocol HTTP --protocol-port 80 lb1
openstack loadbalancer pool create --name pool1 --lb-algorithm ROUND_ROBIN --listener listener1 --protocol HTTP
openstack loadbalancer member create --subnet-id private-subnet --address 192.168.0.9 --protocol-port 80 pool1

(overcloud) [stack@undercloud-1 ~]$ openstack loadbalancer healthmonitor create --delay 5 --max-retries 4 --timeout 10 --type PING pool1
The selected type is not allowed in this deployment: PING (HTTP 400) (Request-ID: req-8a6ee146-466a-45f0-8610-e2592855bce0)

And from the controller logs: /var/log/containers/octavia/api.log

(...)
2019-06-27 13:56:23.914 1 DEBUG wsme.api [req-8a6ee146-466a-45f0-8610-e2592855bce0 - 5db19751bbb94e898545a56db731dca7 - default default] Client-side error: The selected type is not allowed in this deployment: PING format_exception /usr/lib/python2.7/site-packages/wsme/api.py:222
(...)