cmd/juju: fixed capitialisation in upgrade-juju output
cmd/jujud: upgrade error reporting tweaks

- log when a state server has successfully finished waiting for other
  state servers to be ready for upgrade
- ensure that upgrade ALL errors are logged and are reflected in
  status output
- refactored error reporting so that errors are only logged from a
  handful of places
Merge pull request #778 from mjs/upgrade-error-reporting

cmd/jujud: upgrade error reporting tweaks

- log when a state server has successfully finished waiting for other state servers to be ready for upgrade
- ensure that upgrade ALL errors are logged and are reflected in status output
- refactored error reporting so that errors are only logged from a handful of places

http://reviews.vapour.ws/r/47/