On initialization, Config calls the backend showConfig (with --show-show-defaults) to obtain the active and session config state; get_config_dict makes a second call, as it was dependent on the path-relative showConfig(path, ...).

1. The path-relative call is no longer required, due to T2667
2. The nature of default values has been rationalized by T2588

Consequently, the additional call to showConfig can be removed from get_config_dict, relying instead on the data provided at initialization. This will improve performance, as each call to showConfig is on the order of ~50 ms, and moreover, allow a cleaner generalization of Config for off-line testing and the vyos-configd daemon.