Add redirect for IAB v3 restructure.

Change-Id: I65ccc6767408977a9756b217168b819b71816c1f
diff --git a/scripts/app_engine_server/redirects.yaml b/scripts/app_engine_server/redirects.yaml
index 34b16a4..352e9ce 100644
--- a/scripts/app_engine_server/redirects.yaml
+++ b/scripts/app_engine_server/redirects.yaml
@@ -147,12 +147,17 @@
   type: permanent
   comment: redirect to new loc
 
-# new one
 - src: /guide/publishing/licensing.html
   dst: /google/play/licensing/index.html
   type: permanent
   comment: Redirect Licensing docs to new location
 
+# new one
+- src: /google/play/billing/billing_about.html
+  dst: /google/play/billing/index.html
+  type: permanent
+  comment: Redirect Licensing docs to new location
+
 - src: /guide/developing/tools/
   dst: /tools/help/
   type: permanent