ethtool output lacks supported mode info, causes network test wonkiness.

 Note that this is how the network script determines the max speed:
def max_speed(self):
        # Parse ethtool data for max speed since /sys/class/net/DEV/speed only
        # reports link speed.

        # Search for things that look like 100baseSX,
        # 40000baseNX, 10000baseT
        try:
            ethinfo = check_output(['ethtool', self.interface],
                                   universal_newlines=True,
                                   stderr=STDOUT).split(' ')
        except FileNotFoundError:
            logging.warning('ethtool not found! Unable to get max speed')
            ethinfo = None
        except CalledProcessError as e:
            logging.error('ethtool returned an error!')
            logging.error(e.output)
            ethinfo = None
        finally:
            expression = '(\\d+)(base)([A-Z]+)'
            regex = re.compile(expression)
            speeds = [0]
            if ethinfo:
                for i in ethinfo:
                    hit = regex.search(i)
                    if hit:
                        speeds.append(int(hit.group(1)))
            return max(speeds)

Also, on those systems, ethtool is not showing the advertised speeds:

Settings for enP2p1s0f2:
 Supported ports: [ ]
 Supported link modes: Not reported
 Supported pause frame use: No
 Supports auto-negotiation: No
 Advertised link modes: Not reported
 Advertised pause frame use: No
 Advertised auto-negotiation: No
 Speed: 10000Mb/s
 Duplex: Full
 Port: FIBRE
 PHYAD: 0
 Transceiver: external
 Auto-negotiation: off
 Current message level: 0x00000000 (0)

 Link detected: yes

and compare to this from an x86 system:

Settings for enP2p1s0f0:
 Supported ports: [ TP ]
 Supported link modes: 1000baseT/Full
                         10000baseT/Full
 Supported pause frame use: Symmetric
 Supports auto-negotiation: Yes
 Advertised link modes: 1000baseT/Full
                         10000baseT/Full
 Advertised pause frame use: No
 Advertised auto-negotiation: Yes
 Speed: 10000Mb/s
 Duplex: Full
 Port: Twisted Pair
 PHYAD: 0
 Transceiver: external
 Auto-negotiation: on
 MDI-X: Unknown
 Current message level: 0x0000000f (15)
          drv probe link timer
 Link detected: yes

So the bug is actually in the output of ethtool, in that there is no evidence of the supported modes in ethtool output.

One addition, the network test assumes that something with no supported modes listed is a wifi device and assumes no idea of the max speed and doesn't fail on the threshold at that point.