ports not correctly opened after hook failure

[Junien F]

Hi,

If you set services via juju config, and the resulting config fails the check at :

 960 if service_haproxy("check"):

Then haproxy will forget that it has not opened the ports. I think this can be fix easily at :

 934 old_service_ports = get_service_ports()

haproxy should use "opened-ports" here instead of get_service_ports(), which just reads the config and doesn't check which ports are actually opened.

Thanks