Fix navbar editor for RTL layouts.

Remove navigation bar layout XML override which wasn't needed anyway, as
the views in mid_navigation_bar are already reordered based on the
layout direction anyway.

Change-Id: Id57c781d9580fa0cb2eab3bb332daf4136bec321
JIRA:CYAN-2557
Merge "Fix navbar editor for RTL layouts." into cm-11.0