Fix attachments display when using REST API upload endpoint

Using the REST API:

• Create a batch

curl -u Administrator:Administrator -X POST 'http://localhost:8080/nuxeo/api/v1/upload'

• Upload a file and 2 attachments in a batch

curl -u Administrator:Administrator -H 'X-File-Name: BeyondSpaceTravelAgency-RatePlan.docx' -H 'Content-Type: application/octet-stream' -F file=@/path/to/BeyondSpaceTravelAgency-RatePlan.docx -X POST 'http://localhost:8080/nuxeo/api/v1/upload/yourBatchIdHere/0'

...

• Bind files to a new document

curl -u Administrator:Administrator -H 'Content-Type: application/json' -X POST 'http://localhost:8080/nuxeo/api/v1/path/default-domain/workspaces/Contracts/EMEA' -d '{ "entity-type" : "document", "type": "BCContract", "name": "beyond-space-agency", "properties" : { "dc:title": "Beyond Space Travel Agency", "dc:description": "Travel to the infinite and beyond in first class ufos.", "bccontract:startDate": "2015-06-01", "bccontract:endDate": "2016-06-30", "bccontract:contractOwner": "Sarah", "bccontract:customer": [

{"firstName": "Chuck", "name": "Norris", "birthDate": "1968-10-14"}

], "bcsalescommon:amount": "99750", "file:content":

{ "upload-batch": "yourBatchIdHere", "upload-fileId": "0" }

, "files:files" : [ { "file" :

{ "upload-batch": "yourBatchIdHere", "upload-fileId": "1" }

}, { "file" :

{ "upload-batch": "yourBatchIdHere", "upload-fileId": "2" }

} ] } }'

=> Document is created and files are attached
=> BUT going to the files tab, empty names appear