Navbar: Fix MDPI & HDPI landscape layout

Before: http://i.imgur.com/89SmFbX.png
After: http://i.imgur.com/UbuAggD.png

Change-Id: I6623cb97881313886de39a67baa98f7bd4b0696a

Conflicts:

	packages/SystemUI/res/layout/mid_navigation_bar_land.xml