Fix asset_utils when no service_account_json

Change-Id: I0524c96e3a6ab1a342872d5d0d903e87526dffeb
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/256230
Auto-Submit: Ben Wagner aka dogben <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
1 file changed