fix kokoro continuous failure (#2416)
fix kokoro continuous failure (#2416)


dazuma/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/gcloud-ruby,googleapis/google-cloud-ruby,blowmage/gcloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,googleapis/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby,dazuma/google-cloud-ruby