SystemUI: Navigation Bar: Rotate the search light in landscape

The current search light icon is an arrow pointing upwards, so
while in portrait it points to the direction to be swiped to access
Google Now (and the customizable shortcuts), in landscape it points
upward as well which looks out of place, and swiping upwards reveals
that you have to swipe towards the left to access those targets.
Rotate it by 270 degrees to make it point towards the right direction
(i.e. Towards the lockscreen widgets)

Change-Id: I19670fdb1f5ab7814c05264330cb8097a206639a