juju2: command error message (usage) consistency

[David Britton]

3 commands are used to get a controller bootstrapped for MaaS:

dpb@helo:~[0]$ juju add-cloud
error: Usage: juju add-cloud <cloud name> <cloud definition file>
dpb@helo:~[0]$ juju add-cloud hare ~/.ls/juju2.yaml

dpb@helo:~[0]$ juju add-credential
error: Usage: juju add-credential <cloud-name> [-f <credentials.yaml>]
dpb@helo:~[0]$ juju add-credential hare -f ~/.ls/juju2.yaml
credentials updated for cloud hare

dpb@helo:~[0]$ juju bootstrap
error: controller name and cloud name are required
dpb@helo:~[0]$ juju bootstrap hare hare
[...]

2 inconsistencies here would be nice to fix before release:

1) nothing is outputted for `juju add-cloud <valid_params>`. Should output like "Added cloud hare." or something like that.

2) Error message does not list short usage statement for `juju bootstrap`. Should be as easy as using the first line from `juju bootstrap --help`:

Usage: juju bootstrap [options] <controller name> <cloud name>[/region]

[Anastasia (anastasia-macmood)]

Point 1 is a duplicate of bug # 1596039. Marking this report as such.

Point 2 is no longer valid as 'juju bootstrap' from 2.1 will start interactive bootstrap process asking you for further bootstrap details.