Test that ImageStreamMappings handle annotations

Check that

• the annotation image.openshift.io/manifestBlobStored is handled
  • If the annotation is set, the apiserver should remove the manifest from the related `Image` object.

Previous work:

• https://github.com/openshift/origin/blob/bfbbe79bce6ae1d65059072eebb905a8e74eeb07/test/extended/images/imagestream.go#L26