Couple of bug fixes: dnsmasq batt drain + anr

-Apparently, dnsmasq doesn't like it when you leave it running and
there are no connected interfaces... causes massive battery drain in
venturi. So I'm killing dnsmasq when bluetooth is disconnected.

-There is an anr with "Extras" in settings because the sweep2wake
"enable" path is missing. So I'm checking for the path first before
executing shell command.