Code review comment for lp:~axwalk/charms/trusty/ceph/trunk

We can't land this until charm-tools understands storage metadata attributes:

E: Unknown root metadata field (storage)

I however did take a run through the code; see inline comments.

The storage_get and storage_list helpers are not inline with other hookenv functions in that they use "" instead of None for optional paramaters - it would be nice to get that fixed as well.