currently version ids are timestamps, but for storage provided versions
this is not always the case and they might be strings
Signed-off-by: Robin Appelman <robin@icewind.nl>
To make sure that the versions in the legacy backend are shared again we
have to check the storage of a file. Since all shared files are still on
the owners storage.
Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
Allows apps to register version backends for storage types
The existing versions backend is wrapped in a "legacy" backend.
Signed-off-by: Robin Appelman <robin@icewind.nl>