I have configured apache as reverse proxy for galaxy and I also configured apache to access my openldap for authentication. It's working fine but I was getting some trouble to logout the users as explained in the documentation here 

So I tried a different approach by adding this mod_rewrite lines to my apache vhost and it seems to work fine to logout users

It took me some time to figure out this workaround so I send it to the list in case it's useful for anyone else. It would be nice if someone can update the docs. I have verified it works with latest chrome and firefox. It doesn't work with internet explorer 11