Get the stored credentials if any.

def _get_credentials_from_settings(self):
        """Get the stored credentials if any."""
        remember_me = CONF.get('main', 'report_error/remember_me')
        remember_token = CONF.get('main', 'report_error/remember_token')
        username = CONF.get('main', 'report_error/username', '')
        if not remember_me:
            username = ''

        return username, remember_me, remember_token