Code review comment for lp:~cmars/juju-core/no-default-series

Tim,
Please review my proposal for eliminating default series from the juju
client (or pass it along to someone who's up for it). In a nutshell:

- Allow charm.URL to have an implied "empty" series.
- charm.Repository can Resolve them.
- The charm store "resolves" series by using a hard-coded value (for
now).
- A local repository uses the environment config default series.
- It's a client command's responsibility to make sure a charm URL is
resolved before calling the state server with it.

Thanks,
Casey

https://codereview.appspot.com/76860044/