For testing SA Query, the autotest needs the ablility to force
kill (and restart) hostapd without giving it time to deauth its
stations gracefully. A method was added to the HostapdCLI class
which does a killall -9 hostapd, resets the wlnX interface,
and restarts hostapd with the same arguments as it had before.
Make the HostapdCLI class non-static so that each objects corresponds
to a hostapd instance on one network interface (this is independent of
whether the AP instances use one or separate hostapd processes)