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
(cherry picked from commit 4e2d5f83ce284d29b6c84537db61bf43c27121a6)