Before this change if a file was uploaded through a mount, then
deleted externally, trying to upload that file again could give EEXIST
"file already exists".
This was because the file already existing in the cache was confusing
rclone into thinking it already had the file.
The fix is to check that if rclone has a stale cache file then to
ignore it in this situation.
See: https://forum.rclone.org/t/rclone-cant-reuse-filenames/20400
Nick Craig-Wood
2347762b0d