Grouped interfaces now clearly show that they are grouped together by listing all
group members and their state in the check output.
Additionally the new port state degraded has been introduced.
A grouped interface is set to this port state if not all of its members are up.
If all members of a group are down, the grouped interface is also considered down, as usual.
CRIT - Group Status (degraded)(!!), Members: [QLogic 1 10GbE Adapter 2 (down), QLogic 1 10GbE Adapter (up)] 10.00 Gbit/s (wrong speed, expected: 20.00 Gbit/s)(!), in: 0.00 B/s, out: 0.00 B/s