When logging errors, do we want something report-like?

Sometimes we want to log an Error object in a tracing method. But when we do this, nothing recurses to the source() of the error, as would happen if the error had propagated to the top level and we had used tor_error::Report.

I'm labeling this as %Arti 1.1.0: Anticensorship ready since the logs currently have a few "internal programming error" messages, and our current behavior does not make them easy to track down.