greeting for anonymous user is displayed on the sign out page

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It is not relevant to display a message to the user saying "First time here?" when he logs out. A minor bug but a bug anyway ;-) I guess a condition testing if the current page is the logout one or something like that is missing in the method ConnectToSessionMessagesMiddleware.process_request in middleware/anon_user.py

I think that it should be better to replace the logout page by the home page with the message saying "you have been successfully logged out" in the orange message bar on the top of the page.