SkQP: download_model complains when files.checksum is missing

Change-Id: I4fad015181f15e4ffb9c9607723a1313a041621b
Reviewed-on: https://skia-review.googlesource.com/103763
Reviewed-by: Stephan Altmueller <stephana@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
1 file changed