Log attempts where username does not exist as failed login attempts
Log attempts where username does not exist as failed login attempts

(cherry picked from commit c01c1d6074fccc44887b3cf5abfcdb203969748c)
(cherry picked from commit f977848aa6aad5313c50f6290ad004e5f7af92de)

uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend,uroni/urbackup_backend