drive: fix duplication of Google docs on server side copy #4517
drive: fix duplication of Google docs on server side copy #4517

Before this change, rclone was looking for the file without the
extension to see if it existed which meant that it never did.

This change checks the destination file exists firsts, before removing
the extension.

ncw/rclone,ncw/rclone,ncw/rclone,ncw/rclone