Dropbox export imports before exporting

[Eusebius]

When exporting to Dropbox, if a savefile is already present on Dropbox, it is first imported, thus overwriting the currentsave, before exporting anything. Current save is therefore lost unless a backup was made beforehand.

If there is no prior save in Dropbox, export works fine. Manually removing an existing Dropbox save currently seems to circumvent the issue.

(environment: FF 52.9)