Merge pull request #2807 from RosettaCommons/roccomoretti/option_tracer_issue
Fix issue with Tracers and options which aren't found.
With the recent tracer re-org, an unknown option results in an error from the Tracer system, as you attempt to use a tracer that hasn't been initialized from options yet. This PR fixes the double-error that occurrs, by merely printing a warning for uninitialized Tracers, rather than dying.