MSC_Tests: make sgsap interface optional

At the moment the sgsap always enabled in the testsuite. This means the
testsuite will try to connect the SGs interface of osmo-msc on
initalization. If the connection fails, the testcase will fail also.

Unfortunately the related patches that add the SGs interface to osmo-msc
are not yet merged to master. This causes almost all testcases to fail,
so lets have the SGs interface as an option that we can switch on when
the SGs interface patches are merged to master.

Change-Id: I429c0c5250d4b61de8a4d6399f284ce2c87cca93
Related: OS#3645
diff --git a/msc/MSC_Tests.ttcn b/msc/MSC_Tests.ttcn
index bf703e6..96ddc8d 100644
--- a/msc/MSC_Tests.ttcn
+++ b/msc/MSC_Tests.ttcn
@@ -119,6 +119,8 @@
 	charstring mp_mme_name := "mmec01.mmegi0001.mme.epc.mnc070.mcc901.3gppnetwork.org";
 	charstring mp_vlr_name := "vlr.example.net";
 
+	boolean mp_sgsap_enable := false;
+
 	BSSAP_Configurations mp_bssap_cfg := {
 		{
 			sccp_service_type := "mtp3_itu",
@@ -277,7 +279,10 @@
 	f_init_mgcp("MSC_Test");
 	f_init_gsup("MSC_Test");
 	f_init_smpp("MSC_Test");
-	f_init_sgsap("MSC_Test");
+
+	if (mp_sgsap_enable == true) {
+		f_init_sgsap("MSC_Test");
+	}
 
 	map(self:MSCVTY, system:MSCVTY);
 	f_vty_set_prompts(MSCVTY);
@@ -491,7 +496,8 @@
 		ipa_ctrl_ip := mp_msc_ip,
 		ipa_ctrl_port := mp_msc_ctrl_port,
 		ipa_ctrl_enable := true,
-		mm_info := mp_mm_info
+		mm_info := mp_mm_info,
+		sgsap_enable := mp_sgsap_enable
 	};
 	return pars;
 }
@@ -517,8 +523,10 @@
 	connect(vc_conn:SMPP, vc_SMPP:SMPP_CLIENT);
 	connect(vc_conn:SMPP_PROC, vc_SMPP:SMPP_PROC);
 	/* SGs part */
-	connect(vc_conn:SGsAP, vc_SGsAP:SGsAP_CLIENT);
-	connect(vc_conn:SGsAP_PROC, vc_SGsAP:SGsAP_PROC);
+	if (mp_sgsap_enable == true) {
+		connect(vc_conn:SGsAP, vc_SGsAP:SGsAP_CLIENT);
+		connect(vc_conn:SGsAP_PROC, vc_SGsAP:SGsAP_PROC);
+	}
 
 	/* We cannot use vc_conn.start(f_init_handler(fn, id, pars)); as we cannot have
 	 * a stand-alone 'derefers()' call, see https://www.eclipse.org/forums/index.php/t/1091364/ */