Start to use SUA local referencs from 1000 upwards

... which allows us to detect sequence 0 as something that's wrong
(i.e. uninitalized)
diff --git a/src/hnbgw_cn.c b/src/hnbgw_cn.c
index 5c4a77a..c1e9d1c 100644
--- a/src/hnbgw_cn.c
+++ b/src/hnbgw_cn.c
@@ -349,6 +349,7 @@
 	INIT_LLIST_HEAD(&cnlink->map_list);
 	cnlink->T_RafC.cb = cnlink_trafc_cb;
 	cnlink->T_RafC.data = cnlink;
+	cnlink->next_conn_id = 1000;
 	sccp_make_addr_pc_ssn(&cnlink->local_addr, 2, OSMO_SCCP_SSN_RANAP);
 	sccp_make_addr_pc_ssn(&cnlink->remote_addr, 1, OSMO_SCCP_SSN_RANAP);