Bug 2284095

Creating an octavia load-balancer with the ovn provider, adding a health-monitor and then members, octavia creates a neutron hm port in each subnet where a member was added.

Removing the members again, the hm ports do not get cleaned up. The hm removal then cleans up one of the hm ports, the one that is in the subnet where the vip happens to be. The others are still left and do not get cleaned up by octavia. This of course will cause issues when subnets can later not be deleted due to being still populated by the orphaned ports.
The cleanup logic simply does not match the hm port creation logic.


How reproducible:
Always

Steps to Reproduce:
1. Create a load balancer OVN provider with LB + listener + pool
2. Create a member1 from the same subnet as the LB VIP
3. Create another member2 from another subnet
4. Create a HM over the pool in step 1, at this moment we should have two ovn-lb-hm ports 
5. Delete member1 and check if ovn-lb-hm port related to subnet1 is deleted
6. Delete member2 and check if ovn-lb-hm port related to subnet2 is deleted

Actual results:
Some leftover ovn-lb-hm port keeps after deleting all members from the LB

Expected results:
After steps above no ovn-lb-hm ports should be there