Fixed a method syntax in auth.py

lodel/auth/auth.py

     #@note Call a dedicated hook in order to allow session implementation as
     #plugin
     #@thrown AuthenticationFailure
-    def auth_session(self, token)
+    def auth_session(self, token):
         try:
             self.__user_infos = LodelHook.call_hook('lodel2_session_load',
                 caller = self, payload = token)