BTS_Tests: as_l1_sacch(): fix Measurement Report padding

According to 3GPP TS 44.018, section 10.5.2.20, we should pad with zeroes.

Change-Id: I912027fd53b12ff118254e941d6e5e696e1dd410
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 8a3b101..16e3d71 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -1867,8 +1867,8 @@
 			g_pars.l1_pars.ms_power_level, false,
 			g_pars.l1_pars.ms_actual_ta);
 
-		/* TODO: we can use an extension of TTCN-3 for that, i.e. PADDING('2B'O) */
-		var octetstring l2 := f_pad_oct(enc_LapdmFrameAB(valueof(lb)), 21, '2B'O);
+		/* According to 3GPP TS 44.018, section 10.5.2.20, we should pad with zeroes */
+		var octetstring l2 := f_pad_oct(enc_LapdmFrameAB(valueof(lb)), 21, '00'O);
 
 		log("Sending Measurement Report: ", l1h, l2);
 		L1CTL.send(ts_L1CTL_DATA_REQ_SACCH(g_chan_nr, ts_RslLinkID_SACCH(0), l1h, l2));