deployment.sentry['foo/0'] is now returning a list

[Stuart Bishop]

deployment.sentry['foo/0'] now appears to return a list, where previously it would return a Sentry object. This is causing the lp:charms/trusty/cassandra tests to fail.

[Stuart Bishop (stub)]

Not quite.

deployment.sentry['foo/0'] returns an empty list if the foo/0 unit does not exist. The Cassandra tests stopped passing because it assumed the first unit in a deployed service would be cassandra/0, but that has changed with Juju 1.25 where unit numbers will not be reused if you destroy a service and create another with the same name.