Fix Json decode failure in requesting bucket artifacts
Fix Json decode failure in requesting bucket artifacts

This seems to be caused by alt=media which I can not find docs on
https://cloud.google.com/storage/docs/json_api/v1/objects/get#try-it

monopole/test-infra,cblecker/test-infra,pwittrock/test-infra,dims/test-infra,jessfraz/test-infra,BenTheElder/test-infra,fejta/test-infra,kubernetes/test-infra,cblecker/test-infra,jessfraz/test-infra,cjwagner/test-infra,dims/test-infra,cblecker/test-infra,BenTheElder/test-infra,kubernetes/test-infra,kubernetes/test-infra,fejta/test-infra,cjwagner/test-infra,BenTheElder/test-infra,kubernetes/test-infra,BenTheElder/test-infra,pwittrock/test-infra,dims/test-infra,cblecker/test-infra,cblecker/test-infra,cjwagner/test-infra,cjwagner/test-infra,jessfraz/test-infra,dims/test-infra,michelle192837/test-infra,michelle192837/test-infra,pwittrock/test-infra,fejta/test-infra,monopole/test-infra,dims/test-infra,pwittrock/test-infra,fejta/test-infra,pwittrock/test-infra,michelle192837/test-infra,jessfraz/test-infra,cjwagner/test-infra,monopole/test-infra,cblecker/test-infra,kubernetes/test-infra,michelle192837/test-infra,dims/test-infra,fejta/test-infra,jessfraz/test-infra,BenTheElder/test-infra,fejta/test-infra,monopole/test-infra,cjwagner/test-infra,monopole/test-infra,michelle192837/test-infra,kubernetes/test-infra,BenTheElder/test-infra,monopole/test-infra,jessfraz/test-infra,michelle192837/test-infra