Gallery2: use ripple in bottom navigation items

Change-Id: I74c61d153c4c5432793ba107d42a69a7bcf2f748
Signed-off-by: Timi <timi.rautamaki@gmail.com>
diff --git a/res/layout/gallery_main.xml b/res/layout/gallery_main.xml
index 3cbc1e8..6e2b753 100755
--- a/res/layout/gallery_main.xml
+++ b/res/layout/gallery_main.xml
@@ -63,7 +63,6 @@
             android:background="@color/primary"
             android:layout_alignParentBottom="true"
             app:menu="@menu/navigation_items"
-            app:itemBackground="@color/primary"
             app:itemIconTint="@drawable/item_bg"
             app:itemTextColor="@drawable/item_bg" />