Refine pollState when the modem is off.

It had been fixed to not ask the RIL for state if the modem was off
unless we're on IWLAN.  However, the first indication we're on
IWLAN comes via a pollState response.  Modified to also poll
if the pollState trigger came from the RIL (ie, a network state change
notification).

bug:27486486
Change-Id: Ibaed6e2e98d27e651faeeccf71d43e7ff77c938b