Comment 12 for bug 1492180

On ubuntu artful (17.10), both `iwconfig` and `iw dev` report 6Mb/s :

$ iwconfig wlp6s0
wlp6s0 IEEE 802.11 ESSID:"eduroam"
          Mode:Managed Frequency:5.24 GHz Access Point: CC:46:D6:CB:1E:6E
          Bit Rate=6 Mb/s Tx-Power=18 dBm
          Retry short limit:7 RTS thr:off Fragment thr:off
          Power Management:on
          Link Quality=53/70 Signal level=-57 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:18 Missed beacon:0

$ iw dev wlp6s0 link
Connected to cc:46:d6:cb:1e:6e (on wlp6s0)
 SSID: eduroam
 freq: 5240
 RX: 245022251 bytes (1712002 packets)
 TX: 26564 bytes (225 packets)
 signal: -56 dBm
 tx bitrate: 6.0 MBit/s

 bss flags: short-slot-time
 dtim period: 1
 beacon int: 102