Remove the size group where mtu label belongs, so that it can request
enough space when it becomes visible. Since the size group is removed,
filler widget is no longer useful. Remove it as well.
This can be set to 'preserve', 'permanent', 'random' or 'stable'. We
need to handle these values otherwise we can end up with the editor
being un-saveable.
Turn the entry in to a GtkComboBoxText with those items in it, allowing
a mac address to be typed too.
Partial copy of 85b6b659a140a59c3df787062e089a0b4e2a547d from
network-manager-applet.
Firewalld is a Fedora-only daemon, and it doesn't integrate all that
well with Fedora Workstation, the version of Fedora that uses GNOME, so
remove the support.
In Fedora Workstation, firewalld only ever supports one zone, as the
other ones are badly defined, and not translatable or translated.
