Unfortunately, the VPN plugins provide their own .ui files for their
editor pages, so we can't make them look competely GNOME-3-ish. But
the code does try to fix them up a little bit by realigning the
labels.
vpn-helpers.[ch] is nearly identical to network-manager-applet's,
but eventually this code will move into libnm-gtk.
https://bugzilla.gnome.org/show_bug.cgi?id=691285
