The new API submits rebuild transition with new replicas set to be old
(current) replicas plus the provided one. It looks and acts like the
move_tablet API call with several changes:
- lacks the "source" replica argument
- submits "rebuild" transition kind
- cross racks checks are not performed
The 'force' argument is inherited from move_tablet, but is unused now
and is left for future.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>