rapid wireless association changes in my experience), there is a race
where dhclient is in the process of exiting due to the link going down
when the link coming up causes devd to try and start a new one. This
results is the link being up, but no dhclient running.
Work around this race by checking a second time after a one second delay
before refusing to start a dhclient instance due to one already being
running.
MFC after: 1 week
