Fix issue #17397177: BatteryStats reporting error on job start/stop

Dumb, dumb, dumb mistake.

Also fix battery stats wakeup reason tracking to use a SamplingTimer
(like kernel wake locks) so we can track both the duration and count
for each wakeup reason.

Change-Id: I89d69661006dc533622b1b7e68a139166d3a6975