Allow associating a background map/sprite with the root layout.

Change-Id: I9216846e01d7126ffaad9125790f413d8ea8c496
diff --git a/tools/test/topos/regions-bayarea-grid.sh b/tools/test/topos/regions-bayarea-grid.sh
index 923b7d5..c7b4de1 100755
--- a/tools/test/topos/regions-bayarea-grid.sh
+++ b/tools/test/topos/regions-bayarea-grid.sh
@@ -266,10 +266,12 @@
 
 onos ${host} <<-EOF
 
+layout-add root @bayareaGEO
+
 layout-add lC01 +segmentRouting c01
-layout-add lC02 @bayareaGEO c02
-layout-add lC03 . c03
-layout-add lC04 . c04
+layout-add lC02 +segmentRouting c02
+layout-add lC03 +segmentRouting c03
+layout-add lC04 . c04         # testing no-background
 
 layouts