* always use bts->c0 as msg->trx for OML messages

diff --git a/src/abis_nm.c b/src/abis_nm.c
index b506f34..313b9dc 100644
--- a/src/abis_nm.c
+++ b/src/abis_nm.c
@@ -163,6 +163,8 @@
 /* Send a OML NM Message from BSC to BTS */
 int abis_nm_sendmsg(struct gsm_bts *bts, struct msgb *msg)
 {
+	msg->trx = bts->c0;
+
 	return _abis_nm_sendmsg(msg);
 }