getobjecttree doesn't work if there is no any file is uploaded

[cnlangzi]

0box-sdk        [ERROR]  2022/03/16 11:31:40.716329 common.go:35: Object tree response : 400
0box-sdk        [ERROR]  2022/03/16 11:31:40.716480 copyworker.go:102: 400: Object tree error response: Body: {"code":"invalid_parameters","error":"invalid_parameters: Invalid path. Could not find object tree"}
0box-sdk        [ERROR]  2022/03/16 11:31:40.726235 common.go:35: Object tree response : 400
0box-sdk        [ERROR]  2022/03/16 11:31:40.726378 copyworker.go:102: 400: Object tree error response: Body: {"code":"invalid_parameters","error":"invalid_parameters: Invalid path. Could not find object tree"}

reproduce it

• ./zbox newallocation
• ./zbox copy --remotpath / --destpath /dir --allocation $alloc