When there's a disconnect between the version of sources found in a given branch's HEAD (eg., for a project = jbosstools-central) and that same project's latest binaries, the aggregation fails with a somewhat cryptic error about local sources.

Often, however, the reason for the failure is that the aggregation is seeing a newer commit in github than the latest binary built upstream and used to do the aggregation.

So, we should enhance the error message to explain this and suggest the solution.