For sample code see new file contrib/adc/get-rights-and-owner.in-perl.
Despite the name, you can use similar code in a hook also -- comments in
that file will tell you how.
implementation notes:
- check_access now takes an optional last arg "dry_run", which is also
passes through to check_ref
- check_ref returns a "DENIED by ..." instead of die-ing if dry_run is
passed in
- as a side effect, cli_repo_rights is now just a stub calling
check_access (we kept it hanging around for backward compat -- too
much adc pain for too many people if we change it now)
