superuser unable to show status of users models

[Christopher Lee]

As seen at
    http://reports.vapour.ws/releases/issue/57eacb31749a5646c50f38f9

Given a superuser admin who creates a user, if that user add-models a model the admin is able to list the model (using juju list-models) but is unable to show the status of the model (get: ERROR permission denied (unauthorized access)).

To reproduce:

# As admin
$ juju bootstrap --constraints mem=2G lxd/localhost listmodelstest

$ juju add-user newuser1 -c listmodelstest
User "newuser1" added
Please send this command to newuser1:
 ... snip ...

$ juju grant newuser1 addmodel -c listmodelstest

# Now as new user
$ JUJU_DATA=/tmp/newuserstuff juju register ... snip ...

$ JUJU_DATA=/tmp/newuserstuff juju add-model mysweetmodel

$ JUJU_DATA=/tmp/newuserstuff juju list-models
Controller: listmodelstest

Model Cloud/Region Status Access Last connection
mysweetmodel* localhost/localhost available admin never connected

# Back as admin
$ juju list-models -c listmodelstest
Controller: listmodelstest

Model Cloud/Region Status Machines Cores Access Last connection
controller localhost/localhost available 1 - admin just now
default localhost/localhost available 0 - admin 11 hours ago
newuser1/mysweetmodel localhost/localhost available 0 - never connected

$ juju show-status -m listmodelstest:newuser1/mysweetmodel
ERROR permission denied (unauthorized access)

[Horacio Durán (hduran-8)]

I proposed https://github.com/juju/juju/pull/6967