filer: leveldb and hbase may miss files when listing large directories more than 1024

fix https://github.com/chrislusf/seaweedfs/issues/1768

weed/filer/leveldb/leveldb_store.go

@@ -187,11 +187,11 @@ func (store *LevelDBStore) ListDirectoryPrefixedEntries(ctx context.Context, dir
 		if fileName == startFileName && !includeStartFile {
 			continue
 		}
-		lastFileName = fileName
 		limit--
 		if limit < 0 {
 			break
 		}
+		lastFileName = fileName
 		entry := &filer.Entry{
 			FullPath: weed_util.NewFullPath(string(dirPath), fileName),
 		}