Comment 1 for bug 1392544

So this was discussed in IRC, a rough summary is:

This has actually been the behavior for a long time. "default" in "juju get" actually means "is the value currently set the default value, or is it a user specified value". It isn't intended to report the value in config.

We're discussing changing this (to something like 'is-default') in the future command "juju service get" when the CLI is changed to use subcommand syntax.