Add juju status and get-constraints outputs

Signed-off-by: Ante Karamatic <ante.karamatic@canonical.com>
Rearrange openstack plugin so that distribution OpenStack class
contains all non-distribution specific details. Also dropped all
logrotate parts since those are collected by logrotate plugin.

Signed-off-by: Ante Karamatic <ante.karamatic@canonical.com>
Merge pull request #167 from ivoks/juju

Refactored OpenStack plugin