Very minor cleanup of the Runs Controller.
Set the run status message to "Queued" when it has been.

The status message was staying blank until the run was being processed, but we
need to tell the user if the run has been queued straight away.
The worker was failing hard if there was no run log.

If a run is cancelled very quickly there is likely to be no run log on the
server. We don't care if there is no log, but we don't want this to be an error!