Extra options are extracted from the machine configuration for the
network being configured to allow for customized network manager
behavior. The network entries must be filtered to remove non-network
entries (like port forwards) before accessing by index.
Fixes#9546
* ALT Linux platforms is an original rpm based distribution
forked as Mandrake Russian Edition Spring at 2001 year
* Distributions of ALT Linux use etcnet (https://www.altlinux.org/Etcnet) as
internal network configuration system needs for configure_networks support
Chris Roberts
Evgeny Sinelnikov