upgrade-juju output is confusing

[Roger Peppe]

When running juju upgrade-juju, it prints output but it's not clear
what that output signifies.

For example:

 % juju upgrade-juju --version 2.0-beta8.1
 available tools:
     2.0-beta8.1-precise-amd64
     2.0-beta8.1-precise-amd64
     2.0-beta8.1-quantal-amd64
     2.0-beta8.1-quantal-amd64
     2.0-beta8.1-raring-amd64
     2.0-beta8.1-raring-amd64
     2.0-beta8.1-saucy-amd64
     2.0-beta8.1-saucy-amd64
     2.0-beta8.1-trusty-amd64
     2.0-beta8.1-trusty-amd64
     2.0-beta8.1-utopic-amd64
     2.0-beta8.1-utopic-amd64
     2.0-beta8.1-vivid-amd64
     2.0-beta8.1-vivid-amd64
     2.0-beta8.1-wily-amd64
     2.0-beta8.1-wily-amd64
     2.0-beta8.1-xenial-amd64
     2.0-beta8.1-xenial-amd64
     2.0-beta8.1-yakkety-amd64
     2.0-beta8.1-yakkety-amd64
 best version:
     2.0-beta8.1

Does this mean that upgrade-juju has succeeded, or that it wants the user
to make a choice between one of the given versions?
Better not to print anything perhaps, but provide some other way
to get upgrade-juju to print possible versions to upgrade to.

Also, it's not clear to a naive user what is the relationship between
version and tools, and the tools output seems to have a bunch of duplicated
lines.

[Cheryl Jennings (cherylj)]

:( I thought we fixed this via bug #1403655.

[Cheryl Jennings (cherylj)]

Ah, I see. The message of "started upgrade to <version>" is done with logger.Infof. It should be ctx.Infof.

[Anastasia (anastasia-macmood)]

This code no longer exists in Juju 2.