And with that rename calculate_natural_endpoints(const token& search_token, const token_metadata&, can_yield)
to do_calculate_natural_endpoints and make it protected,
With this patch, all its external users call the async version, so
rename it back to calculate_natural_endpoints, and make
calculate_natural_endpoints_sync private since it's being called
only within abstract_replication_strategy.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>