Comment 1 for bug 1719715

https://launchpad.net/+apidoc/devel.html#distro_series says the status can be:

 One of:

    Experimental
    Active Development
    Pre-release Freeze
    Current Stable Release
    Supported
    Obsolete
    Future

I guess artful is now in Pre-release Freeze now, and so getDevelopmentSeries doesn't actually do what we want? I guess we need to enumerate all series instead and find ones that are either in Active Development or Pre-release Freeze.