Bug#717593: Can't install gnome shell extensions from extensions.gnome.org because of root privilege

[r.3 at libertysurf.fr]

actually, gnome-shell really tries to save files in .local/share/gnome-shell I think, as XDG_DATA_DIRS is the only XDG environment variable.
so my problem shall not come from directories rights as I expected. sorry for misleading.