Fix headset button double-click handling with screen off.

Handler only counts awake time, so we need to hold a wake lock while
having messages scheduled to it.

Change-Id: I01fae025830734758a704afaac452b61db3a13f4
Merge "Fix headset button double-click handling with screen off." into cm-11.0
Merge branch "cm-11.0" into kylin