[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 not rql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',
           ask_confirm=False):
    rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',
        ask_confirm=False)