For settings corresponding to devices that have a :carrier property
(ie bond, bridge, infiniband, vlan, and wired), add a :carrier-detect
property specifying how that affects the connection:

  yes: The connection can only be activated when the device
      has carrier, and will be deactivated if the device loses
      carrier (for more than 4 seconds).
  no: The connection ignores carrier on the device; it can be
      activated when there is no carrier, and stays activated
      when carrier is lost.
  on-activate: The connection can only be activated when the
      device has carrier, but it will not be deactivated if the
      device loses carrier.

https://bugzilla.gnome.org/show_bug.cgi?id=688284