[Merge] ~chad.smith/software-properties:ua-status-from-json-impish into software-properties:ubuntu/impish

[Chad Smith]

The proposal to merge ~chad.smith/software-properties:ua-status-from-json-impish into software-properties:ubuntu/impish has been updated.

Commit message changed to:

utils: prefer ua status from status.json. Support schema 0.1 format

Adjust gtk.utils.get_ua_status to prefer reading
/var/lib/ubuntu-advantage/status.json instead of invoking
ua status on the commandline due to a network roundtrip that
is performed while running the command.

This status.json file will exist on all machines attached to an
Ubuntu Advantage subscription.

Unattached machines will persist status.json due to a systemd timer
that will sync current unattached or attached status to
/var/lib/ubuntu-advantage/status.json.

Allow get_ua_status will now also check a _schema_version key from
ua status which will log if the schema version has changed from the
expected version "0.1".

Changes in schema version may imply incompatibility with reading
UA status.

For more details, see:
https://code.launchpad.net/~chad.smith/software-properties/+git/software-properties/+merge/411092
-- 
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~chad.smith/software-properties:ua-status-from-json-impish into software-properties:ubuntu/impish.