Move back to use then authenticated method
    
    Instead of relying on the present of flask.g.authenticated.
    
    The perf gain isn't that important but this change is having consequences
    in a number of places in the code to the point that it is as simple to
    revert this change.
    
    Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr></pingou@pingoured.fr>