help text for juju set-config needs improving

[Peter Matulis]

e.g.:

Usage: juju set-config [options] <service name> <service key>=<value> ...

Summary:
Sets configuration options for a service.

Options:

--config (= )
    Path to YAML service configuration file
-m, --model (= "")
    Model to operate in
--to-default (= false)
    Set service option values to default

Details:
Charms may, and frequently do, expose a number of configuration settings for a service to the user. These can be set at deploy time, but may be set at any time by using the `juju set-config` command. The actual options vary per charm (you can check the charm documentation, or use `juju get-config` to check which options may be set).
If ‘value’ begins with the ‘@’ character, it is interpreted as a filename and the actual value is read from it. The maximum size of the filename is is 5M.
Values may be any UTF-8 encoded string. UTF-8 is accepted on the command line and in referenced files.
See `juju status` for service names.

Examples:

    juju set-config mysql dataset-size=80% backup_dir=/vol1/mysql/backups
    juju set-config apache2 --model mymodel --config /home/ubuntu/mysql.yaml

See also: get-config
          deploy
          status

[Reed O'Brien (reedobrien)]

PR: https://github.com/juju/juju/pull/5120
RB: http://reviews.vapour.ws/r/4559/