hnbgw: Implement validation of [some] counters

Let's use the StatsD_Checker to verify that counters increment when
we expect them to.

Change-Id: Ib0e2dd23802b18f4bd417150d0b62954b1d459a4
diff --git a/hnbgw/osmo-hnbgw.cfg b/hnbgw/osmo-hnbgw.cfg
index 60f0aba..8a9774b 100644
--- a/hnbgw/osmo-hnbgw.cfg
+++ b/hnbgw/osmo-hnbgw.cfg
@@ -16,6 +16,16 @@
  no login
 !
 
+stats interval 0
+stats reporter statsd
+ prefix TTCN3
+ level subscriber
+ remote-ip 127.0.0.1
+ remote-port 8125
+ flush-period 1
+ mtu 1024
+ enable
+
 cs7 instance 0
  point-code 0.23.5