Add a test case for rebuild of instances with volumes

1. Boot a new instance.
2. Create a new volume.
3. Attach the volume to the instance.
4. Rebuild the server using an alternative image.
5. Check that volume is still attached to the instance.
6. Detach the volume and delete it.
7. Delete the server.

Related-Bug: #1440762

Co-Authored-By: Marian Horban <mhorban@mirantis.com>

Change-Id: I50557c69b54003d3409c8e977966f5332f4fe690
1 file changed