database.js: Allow logout

I've no idea why, but this seems to actually log out the person who clicks on
the button even with CORS issues (client and server on different hosts).
However in such a case the user is not properly redirected: indeed this does
not solve the CORS issue so the logout process doesn't complete.

Fix #2477
29 jobs for feature-sc/2477-basic-fix-logout in 52 minutes and 52 seconds (queued for 4 seconds)