concurrent downloads using same name are not handled

[caramba_bk@…]

There are sometimes two distinct torrents using the same download name, probably providing largely the same content, although not exactly identical. Deluge doesn't seem to handle this, so all files from both torrents are merged into a single download directory. Also, when one of the torrents finish, the directory might be moved and so causes the remaining torrent to fail when it has nowhere to continue writing its files.

Deluge should handle this situation, at least by appending a ".[n]" to a duplicate directory name before it is created. Like numbered backups for the cp command. This assignment must be atomic.

[Cas]

duplicate of #856