Allow translucent navigation bar in landscape mode.

Change-Id: I5388f3f8a34533624619714bacfba52f95fc6d85

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/BarTransitions.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarTransitions.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java