error condition for delete of VHR when VCR is in checked-in collection

Hi,

considering:

- a versioned controlled checked-in collection /a
- a version controlled resource /a/b with a version history resource of
/vhr/123
- a server that handles deletion of version histories as request to
un-version-control the VCR

What should happen upon a DELETE on /vhr/123?

- this would be considered to change the state of /a/b from being
version-controlled to not being version-controlled, however the parent
collection isn't checked out

- returning Conflict with error condition
DAV:cannot-modify-checked-in-parent seems to be a valid approach, however
doesn't fit optimally (because the request was sent to /vhr/123, and /a --
which causes the error as not bein checked out -- isn't a parent collection
of the request URI).

Julian