range_tombstone: Drop without-link constructor
range_tombstone: Drop without-link constructor

The thing was used to move a range tombstone without detaching it
from the containing list (well, intrusive set). Now when the linkage
is gone this facility is no longer needed (and actually no longer
used).

Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla