osmo-hnbgw.cfg: set local-ip to 0.0.0.0

Make the config work out of the box for anyone.

Related: OS#3369
Change-Id: I354140f014854f1755b649e40a65e5d88b99c0ec
diff --git a/doc/examples/osmo-hnbgw.cfg b/doc/examples/osmo-hnbgw.cfg
index cba7f51..9286b2a 100644
--- a/doc/examples/osmo-hnbgw.cfg
+++ b/doc/examples/osmo-hnbgw.cfg
@@ -21,5 +21,5 @@
  logging level lstats notice
 hnbgw
  iuh
-  local-ip 10.23.24.1
+  local-ip 0.0.0.0
   hnbap-allow-tmsi 1