[web/ajax] don't override any status code with 500 in ajax_error_handler
If the request produced an error such as Unauthorized or NotFound,
core_handle sets an appropriate status_out. Which is then overridden by
the ajax error handler.
if versions_map['cubicweb'][0] == (3, 7, 4):
config['http-session-time'] *= 60
config['cleanup-session-time'] *= 60
config['cleanup-anonymous-session-time'] *= 60