sgsn: use vty cmd `reset sgsn state`.

Cleans most of the sgsn state.
Depends on the SGSN commit I92096f3f6ea49e75676e30e9921d00210bac5382.

Change-Id: Idff3de6f1b8f5cb503edc5c6256ce2bf7ec7aaa2
diff --git a/sgsn/SGSN_Tests.ttcn b/sgsn/SGSN_Tests.ttcn
index edc19bc..1453456 100644
--- a/sgsn/SGSN_Tests.ttcn
+++ b/sgsn/SGSN_Tests.ttcn
@@ -206,6 +206,7 @@
 	map(self:SGSNVTY, system:SGSNVTY);
 	f_vty_set_prompts(SGSNVTY);
 	f_vty_transceive(SGSNVTY, "enable");
+	f_vty_transceive(SGSNVTY, "reset sgsn state");
 	f_vty_config(SGSNVTY, "sgsn", "auth-policy remote");
 }
 
@@ -263,12 +264,12 @@
 		sgsn_role := false
 	};
 
+	f_init_vty();
 	f_init_gb(g_gb[0], "SGSN_Test-Gb0", 0);
 	f_init_gb(g_gb[1], "SGSN_Test-Gb1", 1);
 	f_init_gb(g_gb[2], "SGSN_Test-Gb2", 2);
 	f_init_gsup("SGSN_Test");
 	f_init_gtp("SGSN_Test");
-	f_init_vty();
 	f_vty_enable_echo_interval(g_use_echo);
 }