MFH: r535967

Chase src r361272:

Silence the once per second CTRL-EVENT-SCAN-FAILED errors when the WiFi
radio is disabled through the communication device toggle key (also known
as the RF raidio kill button). Only the CTRL-EVENT-DISCONNECTED will be
issued.

Submitted by: avg
Reported by: avg
Approved by: portmgr (joneum)