oslo.vmware.image_transfer uses image service's private internal interfaces

[Jay Pipes]

oslo.vmware.image_transfer's classes and methods take an image_service parameter that is actually the the *internal* nova.image.glance.GlanceImageService manager object, not the *public* nova.image.API object. This means that the library is depending on interfaces that can and do change.

Anywhere that uses image_service in image_transfer module needs to be change to be image_api and use the public interfaces in nova.image.API.

[Radoslav Gerganov (rgerganov)]

@Jay Thanks for filing this. I have submitted the following patch:

https://review.openstack.org/#/c/130726

The image_transfer module is used only in the Nova driver, so I suggest the following plan to address the problem:
1) Rework image_transfer to accept both nova.image.API and the old private interface. This is needed to prevent breaking Nova tempest which is using the latest oslo.vmware
2) Fix the Nova driver to pass nova.image.API when using image_transfer
3) Drop the support for the old private interface in oslo.vmware and use only nova.image.API

Please let me know what do you think about this. Thanks!