* Updatable is now named UpdaterType
* UPDATER_IS_OPTION is now assumed to always be true
While an updater can be a non-optional struct, being an
updater, all its fields are also Updaters, so after
expanding all levels of nesting, the resulting list of
fields can only contain optional values.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>