Always return RecentsView to translation 0 on drag end

After reaching overview, we let the user translate RecentsView
if they continue dragging around. But when they let go, we need
to return RecentsView to translation 0 since that's no longer
part of the state machine.

Change-Id: I30b51485339a3b6c3dd52bda113b1a05b6e885fa
1 file changed