Comment 5 for bug 1623560

On further examination (thank you, mgz!), rackspace bootstrap for images metadata from http://5d117a7efe5779e2018e-77a1198a3891c2a6e76d39896aa23783.r47.cf1.rackcdn.com/images/streams/v1/com.ubuntu.cloud-released-imagemetadata.json needs to have image-stream config property to be set to "custom" as this is the stream value according to content_id.