cmd/juju: status: gather basic machine properties
This proposal adds the ability to gather basic machine
properties.
% juju status
machines:
"0":
dns-name: ec2-50-16-84-143.compute-1.amazonaws.com
instance-id: i-0ea58c76
services: {}
nb. The key of the machines map is a string, not an int, which
is an incompatability with the current pythonic output. This
will be addressed shortly.
R=fwereade, niemeyer
CC=
https://codereview.appspot.com/6419069