Remove a redundant call to TableFileName in CompactionJob::FinishCompactionOutputFile (#4925)

Summary:
While stepping through the code I noticed that there is a redundant call to TableFileName.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4925

Differential Revision: D13845749

Pulled By: sagar0

fbshipit-source-id: 31db45716b4d720e0e0350dd457b49d6f1848e7d

db/compaction_job.cc

@@ -1405,10 +1405,7 @@ Status CompactionJob::FinishCompactionOutputFile(
   auto sfm =
       static_cast<SstFileManagerImpl*>(db_options_.sst_file_manager.get());
   if (sfm && meta != nullptr && meta->fd.GetPathId() == 0) {
-    auto fn =
-        TableFileName(sub_compact->compaction->immutable_cf_options()->cf_paths,
-                      meta->fd.GetNumber(), meta->fd.GetPathId());
-    sfm->OnAddFile(fn);
+    sfm->OnAddFile(fname);
     if (sfm->IsMaxAllowedSpaceReached()) {
       // TODO(ajkr): should we return OK() if max space was reached by the final
       // compaction output file (similarly to how flush works when full)?