973402 - Handle CallReport.progress with value of {} or None

https://bugzilla.redhat.com/show_bug.cgi?id=973402

The *CallReport.progress* is initialized as *progress or {}*.  So, {} is a valid value for the progress report.  After reproducing, I verfied that the agent is not passing an invalid progress report.  Instead, we see this error when the CLI polls the tasks and attempts to render the *CallReport.progress* report before it is ever updated by the agent.  In light of this, I believe it's safe to only render the progress report when it's not *None* and not *{}*.