Comment 3 for bug 1840416

compare the failed case and passed case , it seems the clue is 2nd kernel trigging
wlp2s0: deauthenticated from 3c:ce:73:48:04:60

# from journalctl.log:
 八 16 13:13:38 u-XPS-13-9380 kernel: wlp2s0: deauthenticated from 3c:ce:73:48:0e:40 (Reason: 1=UNSPECIFIED)
 八 16 13:13:39 u-XPS-13-9380 wpa_supplicant[11018]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=BEACON_HINT type=UNKNOWN
 八 16 13:13:43 u-XPS-13-9380 wpa_supplicant[11018]: wlp2s0: SME: Trying to authenticate with 3c:ce:73:48:04:60 (SSID='Canonical-2.4GHz-g' freq=2412 MHz)
 八 16 13:13:43 u-XPS-13-9380 kernel: wlp2s0: associated
 八 16 13:13:43 u-XPS-13-9380 kernel: wlp2s0: deauthenticated from 3c:ce:73:48:04:60 (Reason: 2=PREV_AUTH_NOT_VALID)
 八 16 13:13:43 u-XPS-13-9380 wpa_supplicant[11018]: wlp2s0: CTRL-EVENT-DISCONNECTED bssid=3c:ce:73:48:04:60 reason=2
 八 16 13:13:43 u-XPS-13-9380 wpa_supplicant[11018]: wlp2s0: WPA: 4-Way Handshake failed - pre-shared key may be incorrect
 八 16 13:13:43 u-XPS-13-9380 wpa_supplicant[11018]: wlp2s0: CTRL-EVENT-SSID-TEMP-DISABLED id=0 ssid="Canonical-2.4GHz-g" auth_failures=1 duration=10 reason=WRONG_KEY

# compare to the latest successful rekey in journalctl.log:
 八 14 11:07:33 u-XPS-13-9380 kernel: wlp2s0: deauthenticated from a4:56:30:cc:0f:30 (Reason: 2=PREV_AUTH_NOT_VALID)
 八 14 11:07:33 u-XPS-13-9380 wpa_supplicant[907]: wlp2s0: SME: Trying to authenticate with 3c:ce:73:48:0e:40 (SSID='Canonical-2.4GHz-g' freq=2437 MHz)
 八 14 11:07:33 u-XPS-13-9380 kernel: wlp2s0: associated
 八 14 11:07:33 u-XPS-13-9380 NetworkManager[906]: <info> [1565752053.7303] device (wlp2s0): supplicant interface state: associating -> 4-way handshake