pgw: Don't expect Gx messages during delete of unknwon session

Same approach as implemented for GGSN_Tests in
10ec96e24b7d7fc8dd4fe6e023cc06514f53c66e.

Change-Id: I7ad1fcae612a562d6643f9f01db3a4e7941f3666
diff --git a/pgw/PGW_Tests.ttcn b/pgw/PGW_Tests.ttcn
index 2b74418..775b904 100644
--- a/pgw/PGW_Tests.ttcn
+++ b/pgw/PGW_Tests.ttcn
@@ -378,7 +378,8 @@
 /* delete the session from the PGW */
 private function f_delete_session(template (omit) OCT1 tx_cause := omit,
 				  template (present) OCT4 exp_teid,
-				  template (present) OCT1 exp_cause) runs on PGW_Session_CT {
+				  template (present) OCT1 exp_cause,
+				  boolean expect_diameter := true) runs on PGW_Session_CT {
 	var template (value) FullyQualifiedTEID fteid_c_ie
 	fteid_c_ie := ts_GTP2C_FTEID(FTEID_IF_S5S8_SGW_GTPC, g_teic, 0,
 					f_inet_addr(mp_local_hostname_c), omit);
@@ -388,7 +389,7 @@
 					  teid_list := {}, bearer_id := 1);
 
 	GTP2.send(g2c);
-	if (DIAMETER_PROC.checkstate("Connected")) {
+	if (DIAMETER_PROC.checkstate("Connected") and expect_diameter) {
 		as_DIA_CCR(TERMINATION_REQUEST);
 	}
 	alt {
@@ -564,7 +565,7 @@
 private function f_TC_deleteSession_unknown() runs on PGW_Session_CT {
 	g_teic := f_gtp2_allocate_teid();
 	g_teic_remote := f_rnd_octstring(4);
-	f_delete_session(omit, '00000000'O, '40'O /* Context Unknown */);
+	f_delete_session(omit, '00000000'O, '40'O /* Context Unknown */, false);
 	setverdict(pass);
 }
 testcase TC_deleteSession_unknown() runs on PGW_Test_CT {