Suppress `curl`-output and show what's currently downloaded on stderr

[Ma27]

When generating reports for rather big jobsets (with many failures), the progress-bar from curl isn't very helpful and IMHO rather distracting.

This change sets curl into silent-mode and prints to stderr what file is about to get downloaded.

[samueldr]

Thanks, haven't tested it, but the change is innocuous, and self-explanatory.