With this patch, when a resource entry does not specify a "url" field, there is no file downloaded. This is necessary infrastructure for gem5-resources which do not have specific files/directories to be downloaded but exist solely in the resources.json file. Change-Id: I0d92e830bfcef750119078b8c226b0659ba7f6cb Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67338 Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu> Maintainer: Bobby Bruce <bbruce@ucdavis.edu>