ci-fairy: Fix minio cp command when there's no list permissions

Before this patch, in order to upload files we were listing all buckets and also all objects in the destination bucket.

The user may not necessarily have access for listing even if the upload would have been fine, thus preventing the copy to be performed.

Perform the listings lazily so we can still copy.

Squashed are several fixes and test improvements by Benjamin Tissoires.

Signed-off-by: Tomeu Vizoso tomeu.vizoso@collabora.com Signed-off-by: Benjamin Tissoires benjamin.tissoires@gmail.com