repair: Stop the nodes that have run repair_row_level_start
repair: Stop the nodes that have run repair_row_level_start

It is ok to run repair_row_level_stop unconditionally. The node that
hasn't received the repair_row_level_start will simply return an error
that the repair_meta_id is not found. To avoid the unnecessary
repair_row_level_stop verb, we can stop the nodes have run
repair_row_level_start. This also makes the error message less
confusing.

For example:

Before:

INFO 2020-03-09 15:55:43,369 [shard 0] repair - repair id 1 on shard 0
     failed: std::runtime_error (get_repair_meta: repair_meta_id 8 for
     node 127.0.0.4 does not exist)
INFO 2020-03-09 15:55:43,369 [shard 0] repair - repair id 1
     failed: std::runtime_error ({shard 0: std::runtime_error
     (get_repair_meta: repair_meta_id 8 for node 127.0.0.4 does not
     exist)})
WARN 2020-03-09 15:55:43,369 [shard 0] repair - repair id 1 to
     sync data for keyspace=ks, status=failed, keyspace does not exist
     any more, ignoring it: std::runtime_error ({shard 0:
     std::runtime_error (get_repair_meta: repair_meta_id 8 for node
     127.0.0.4 does not exist)})

After:

INFO 2020-03-09 16:09:09,217 [shard 0] repair - repair id 1 on shard 0 failed:
     std::runtime_error (Failed to repair for keyspace=ks, cf=cf,
     range=(9041860168177642466, 9044815446631222376])
INFO 2020-03-09 16:09:09,217 [shard 0] repair - repair id 1 failed:
     std::runtime_error ({shard 0: std::runtime_error (Failed to repair
     for keyspace=ks, cf=cf, range=(9041860168177642466,
     9044815446631222376])})
WARN 2020-03-09 16:09:09,217 [shard 0] repair - repair id 1 to sync data
     for keyspace=ks, status=failed, keyspace does not exist any more,
     ignoring it: std::runtime_error ({shard 0: std::runtime_error
     (Failed to repair for keyspace=ks, cf=cf,
     range=(9041860168177642466, 9044815446631222376])})

Refs #5942

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