As a preparation to replacing repair_info with shard_repair_task_impl, type of _repairs in repair module is changed from std::unordered_map<int, lw_shared_ptr<repair_info>> to std::unordered_map<int, tasks::task_id>.
As a preparation to replacing repair_info with shard_repair_task_impl, type of _repairs in repair module is changed from std::unordered_map<int, lw_shared_ptr<repair_info>> to std::unordered_map<int, tasks::task_id>.