Inspect OpenStack status fields when discovering services

[stevesloka]

OpenStack resources have a couple of status fields that we might have to inspect to determine whether we should route traffic to that LB or endpoint.

Load balancers have admin_state_up, provisioning_status and operating_status fields. Listeners, pools and pool members all have an admin_state_up field.

[alexbrand]

Load balancer fields and possible values:

• admin_state_up: true, false
• operating_status: ONLINE, OFFLINE
• provisioning_status: ACTIVE, PENDING_CREATE, ERROR

Listener fields and possible values:

• admin_state_up: true, false

Pool fields and possible values:

• admin_state_up: true, false

Pool Member fields and possible values:

• admin_state_up: true, false