test_reject_concurrency: missing assert

I broke this test during dev and saw the failure being noticed only in the next
test when DTAP is expected again. Verify success right there, instead.

Change-Id: Ifdde3a6fa5835203c34c40db77761f2e90c0d5ff

tests/msc_vlr/msc_vlr_test_reject_concurrency.c

@@ -219,6 +219,7 @@ static void test_reject_cm_during_lu()
 	ms_sends_msg("05247803305886089910070000006402");
 	VERBOSE_ASSERT(lu_result_sent, == RES_NONE, "%d");
 	VERBOSE_ASSERT(cm_service_result_sent, == RES_NONE, "%d");
+	VERBOSE_ASSERT(dtap_tx_confirmed, == true, "%d");
 	EXPECT_CONN_COUNT(1);
 
 	BTW("The first LU can still complete");

tests/msc_vlr/msc_vlr_test_reject_concurrency.err

@@ -333,6 +333,7 @@ DMM IMSI:901700000004620: subscr_conn_release_when_unused: conn still being esta
 DREF IMSI:901700000004620: MSC conn use - dtap == 1 (0x4)
   lu_result_sent == 0
   cm_service_result_sent == 0
+  dtap_tx_confirmed == 1
   llist_count(&net->subscr_conns) == 1
 ---
 - The first LU can still complete