Migrate gce-release-1.5 jobs to prow (#2880)
Migrate gce-release-1.5 jobs to prow (#2880)


GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid,GoogleCloudPlatform/testgrid