StorageGroup.list_candidate_adapter_ports() raises KeyError for FC-type storage groups

[andy-maier]

FC-type storage groups do not have a property "candidate-adapter-port-uris". The StorageGroup.list_candidate_adapter_ports() method accesses that property unconditionally and raises KeyError for FC-type storage groups.

While the method is documented to apply only to FCP-type storage groups, it leaves it open what happens when called for FC-type storage groups. The KeyError that is raised is not documented.

Proposal: The method should return None in case of an FC-type storage group, and document that.