hunt for ad-hoc station on plenary.

The ad-hoc stations are also found at today's plenary. I attached the
station information its announce SSID which is seen from the center of
the plenary room at 20:50JST. I guess it is not harmful, since the ad-hoc
station is not used "IETF" as its SSID.

However, I recommend that the terminal should stop it.

IETF-test                               02:02:2D:27:43:A0       10      34      
Ad-hoc