SIP arrange: dragging a folder hangs forever if the REST call fails
|Google Code Legacy ID:||Pull Request:|
When a folder is dragged to the arrangement panel in SIP arrange, if the REST call returns a failed response, the dragging operation hangs forever. This results in the dragged folder remaining stuck in place and the "loading" icon remaining forever.
Archivematica is returning a 500 error containing HTML instead of a JSON response; there should be error handling on the Archivematica side. Additionally, the JS should do some handling of a failed response.