Code review comment for ~freyes/charm-mongodb:status-fix

Hi Stuart,

I addressed your comments, except some of the changes to the messages printed to the users, mostly because those were chosen by Mario and some of them align better with what we see in other charms (e.g. "Unit is ready...")

The functional tests log can be reviewed at http://paste.ubuntu.com/p/bn6hbtDw4g/

Best,

PS: I don't have merge privileges, so if you are OK with this MP would be great if you could merge it and publish the charm into the charmstore.