Use new, consistent assets for adding a bookmark.

Change-Id: I08b492a792e518acb53a69346d51c8c88c06b75e
diff --git a/res/layout/bookmark_thumbnail.xml b/res/layout/bookmark_thumbnail.xml
index abbbb45..8dc5564 100644
--- a/res/layout/bookmark_thumbnail.xml
+++ b/res/layout/bookmark_thumbnail.xml
@@ -44,7 +44,7 @@
         <ImageView
             android:layout_height="wrap_content"
             android:layout_width="wrap_content"
-            android:src="@drawable/ic_tab_browser_bookmark_selected"
+            android:src="@drawable/ic_list_bookmark"
             />
         <TextView
             android:layout_height="wrap_content"