Improve handling of duplicate within the same folder.

In a folder synced with Drive, from Web UI, uploader "filename.doc".
Then upload "toto.doc" as a sibling document.

Observe the two documents are synced locally properly.

Then update toto.doc with the same filename.doc file.

Locally toto.doc is removed, but no error is displayed due to the fact that the new filename.doc cannot be created at the same place.

Fix

• In conflicts and error screen, mention the duplicate and process a link to the server to let the user update with a different filename.

Improvement

• rename locally the file with a _0 suffix that doesn't affect the repository filename.