sgsn: Fix syntax errors introduced in PDP Context Act patches

those were undetected as 'sgsn' is not yet part of the subdirectory
list in the master Makefile :/

Change-Id: I46b2baa10cc5a20cd0cb9c0bf32cc0e1a19d38e6
diff --git a/sgsn/SGSN_Tests.ttcn b/sgsn/SGSN_Tests.ttcn
index 9209c69..138b63b 100644
--- a/sgsn/SGSN_Tests.ttcn
+++ b/sgsn/SGSN_Tests.ttcn
@@ -795,16 +795,16 @@
 		}
 	}
 	alt {
-	[exp_rej] BSSGP.receive(tr_BD_L3(tr_SM_ACT_PDP_REJ(apars.tid, apars.exp_rej_cause))) {
+	[exp_rej] BSSGP.receive(tr_BD_L3_MT(tr_SM_ACT_PDP_REJ(apars.tid, apars.exp_rej_cause))) {
 		setverdict(pass);
 		}
-	[exp_rej] BSSGP.receive(tr_BD_L3(tr_SM_ACT_PDP_ACCEPT)) {
+	[exp_rej] BSSGP.receive(tr_BD_L3_MT(tr_SM_ACT_PDP_ACCEPT)) {
 		setverdict(fail, "Unexpected PDP CTX ACT ACC");
 		}
-	[not exp_rej] BSSGP.receive(tr_BD_L3(tr_SM_ACT_PDP_REJ(apars.tid, ?))) {
+	[not exp_rej] BSSGP.receive(tr_BD_L3_MT(tr_SM_ACT_PDP_REJ(apars.tid, ?))) {
 		setverdict(fail, "Unexpected PDP CTX ACT FAIL");
 		}
-	[not exp_rej] BSSGP.receive(tr_BD_L3(tr_SM_ACT_PDP_ACCEPT(apars.tid, apars.sapi))) {
+	[not exp_rej] BSSGP.receive(tr_BD_L3_MT(tr_SM_ACT_PDP_ACCEPT(apars.tid, apars.sapi))) {
 		setverdict(pass);
 		}
 	}