[r=menno.smits],[bug=1302005] cmd/juju: deprecate --series, added --upload-series
Emit a deprecation warning to stderr when --series is used
To make testing easier an interface is now used to allow the calls
made by BootstrapCommand.Run to environs/bootstrap to be mocked out.
https://codereview.appspot.com/94060044/
R=thumper