Use the right level (L0) for files written during WAL recovery (faceb…

…ook#8187)

Summary:
As the name of `DBImpl::WriteLevel0TableForRecovery` suggests, the resulting table file
should be placed on L0. However, the argument `level` passed to `BuildTable()` is -1.

We need to correct this since the level information will be useful to determine file placement.

Pull Request resolved: facebook#8187

Test Plan: make check

Reviewed By: ltamasi

Differential Revision: D27748570

Pulled By: riversand963

fbshipit-source-id: e1cd23128a8de31f14b1edc2ea92754c154e4f10

db/db_impl/db_impl_open.cc

@@ -1383,7 +1383,7 @@ Status DBImpl::WriteLevel0TableForRecovery(int job_id, ColumnFamilyData* cfd,
           mutable_cf_options.compression_opts, paranoid_file_checks,
           cfd->internal_stats(), TableFileCreationReason::kRecovery, &io_s,
           io_tracer_, &event_logger_, job_id, Env::IO_HIGH,
-          nullptr /* table_properties */, -1 /* level */, current_time,
+          nullptr /* table_properties */, 0 /* level */, current_time,
           0 /* oldest_key_time */, write_hint, 0 /* file_creation_time */,
           db_id_, db_session_id_, nullptr /*full_history_ts_low*/,
           &blob_callback_);