Only start one WifiClientScanner

*) Fixes unexpected soft reboots.
E/AndroidRuntime(18586): *** FATAL EXCEPTION IN SYSTEM PROCESS: WifiClientScanner
E/AndroidRuntime(18586): java.lang.IllegalStateException: Cannot execute task: the task is already running.
E/AndroidRuntime(18586):     at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:576)
E/AndroidRuntime(18586):     at android.os.AsyncTask.execute(AsyncTask.java:535)
E/AndroidRuntime(18586):     at com.android.server.connectivity.Tethering$WifiClientScanner.handleMessage(Tethering.java:596)
E/AndroidRuntime(18586):     at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime(18586):     at android.os.Looper.loop(Looper.java:136)
E/AndroidRuntime(18586):     at android.os.HandlerThread.run(HandlerThread.java:61)

*) Remove unnecessary mDoScan class member variable.

Change-Id: I17ab368366b9a3456a625974c461783c428efec2
SystemUI: fix double tap to sleep not working with secure lock screen

Double tap to sleep on status bar would only work on secure lockscreens if the
slider brightness control was enabled.

Change-Id: I7c4dc5b2f559aafae819422d747f92ac59631ffd
Signed-off-by: Roman Birg <roman@cyngn.com>

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBar.java