gbproxy: Fix SGSN side initialization for more than one SGSN

Change-Id: I4c64bf02a805a959626f6915d9dd72aa7622b24a
diff --git a/gbproxy/GBProxy_Tests.ttcn b/gbproxy/GBProxy_Tests.ttcn
index bd56510..cec3124 100644
--- a/gbproxy/GBProxy_Tests.ttcn
+++ b/gbproxy/GBProxy_Tests.ttcn
@@ -351,7 +351,7 @@
 
 	f_init_vty();
 	for (i := 0; i < lengthof(mp_nsconfig_sgsn); i := i+1) {
-		f_init_gb_sgsn(g_sgsn[0], "GbProxy_Test", 0);
+		f_init_gb_sgsn(g_sgsn[i], "GbProxy_Test", i);
 	}
 	f_sleep(4.0);
 	for (i := 0; i < lengthof(mp_nsconfig_pcu); i := i+1) {