"Update standard folders" should add language links to folders, not rename them

Submitted by Papou

Assigned to Alexander Larsson @alexl

This was originally reported in: https://bugs.launchpad.net/ubuntu/+source/xdg-user-dirs/+bug/556933 (which, I'm afraid, someone turned into a mess)

xdg-user-dirs tries to rename standard folders (e.g. Desktop to Bureau (French), among other languages and folders).

Renaming standard folders is incorrect because :

there may exist references to their files that would become invalid if renamed
if such files exist, xdg-user-dirs quite rightly does not rename the folder but just creates the new name
but then the user's files seem to disappear
and, for the same reason, the user cannot move his files harmlessly
similarly, there may be references to the folder itself, even if empty
and in fact, the Internet is full of references to ~/Desktop (which introducing xdg-user-dirs made invalid) (that's why those folders are called "standard": their names mustn't change)

The correct way is obviously:

to create symbolic links such as Bureau -> Desktop (instead of renaming)
to never remove the symbolic link afterwards (in case references have been made to it)

Temporary workaround: it almost already works: this is a proof of concept: If, before xdg-user-dirs comes to play,

one creates the symbolic link (Bureau -> Desktop)
one makes sure to keep the folder (Desktop) nonempty (e.g. with hidden file), then xdg-user-dirs will not modify any name and the system will work superbly.