BTS_Tests_LAPDm.TC_nr_seq_error: Fix test

Related: OS#5968
Change-Id: I4cdff6ab607e158d4956a1bd87f74e9e75579cff
diff --git a/bts/BTS_Tests_LAPDm.ttcn b/bts/BTS_Tests_LAPDm.ttcn
index b4c2c33..2e984d1 100644
--- a/bts/BTS_Tests_LAPDm.ttcn
+++ b/bts/BTS_Tests_LAPDm.ttcn
@@ -801,6 +801,11 @@
 	/* SAPI = 0, C = 1, P = 0, M = 0,  L = N201, N(S) = 0, N(R) = 1.  * */
 	LAPDM.send(t_PH_DATA(0, false, ts_LAPDm_I(sapi, c_r:=cr_MO_CMD, p:=false,
 						  nr:=1, ns:=0, l3:=l3_mo)));
+	/* LAPD indicates the data and then indicates error with sequence error cause. */
+	RSL.receive(tr_RSL_DATA_IND(g_chan_nr, link_id, l3_mo));
+	RSL.receive(tr_RSL_ERROR_IND(g_chan_nr, link_id, '07'O));
+	/* Release RSL link. */
+	RSL.send(ts_RSL_REL_REQ(g_chan_nr, link_id));
 
 	/* The BTS may: a)   send a DISC frame within N200×T200; */
 	/* DISC SAPI = 0, C = 0, P = 1, M = 0, L = 0. */