Fix periodically disappearing status icons.

Occasionally the animation listener wasn't being told that
the ticker animation had completed; this callback was
essential to keeping the status bar's internal state correct
(namely, setting mTicking=false). The safest thing to do is
simply set mTicking to false immediately upon tickerDone()
or tickerHalting().

Bug: 2915280
Change-Id: I997911b12fa2985fa83b42154fb3485220886219