If the provider claims to provide :ip6 but it doesn't (e.g. foreman_digitalocean, don't tick IPv6), then this still throws an error if `value.blank?` and there's another blank value in the database. Don't call it if the value's blank?  ``` 2016-11-01T14:36:30 c50b235a [sql] [W] ip6  is already used by  ``` 