ggsn_tests: Remove incomplete user plane testing code

In commit 0b7545dff13394fcaac2a9f904fe6858bca7d661 I accidentially
committed incomplete support for user plane (GTP-U) testing to
the GGSN test.

This code has caused the jenkins tests since August 26th to fail,
let's revert it until this is fully implemented + tested.
diff --git a/ggsn_tests/GGSN_Tests.cfg b/ggsn_tests/GGSN_Tests.cfg
index 6954e1d..a7f4681 100644
--- a/ggsn_tests/GGSN_Tests.cfg
+++ b/ggsn_tests/GGSN_Tests.cfg
@@ -11,14 +11,13 @@
 system.*.lazy_conn_id_handling := "YES"
 
 [MODULE_PARAMETERS]
-GGSN_Tests.m_bind_ip_gtpc := "172.18.0.202"
-GGSN_Tests.m_bind_ip_gtpu := "172.18.0.202"
-GGSN_Tests.m_ggsn_ip_gtpc := "172.18.0.201"
-GGSN_Tests.m_ggsn_ip_gtpu := "172.18.0.201"
-GGSN_Tests.m_pdn_sock_host_v4 = "172.17.0.2"
+GGSN_Tests.m_bind_ip_gtpc := "127.0.42.1"
+GGSN_Tests.m_bind_ip_gtpu := "127.0.42.1"
+GGSN_Tests.m_ggsn_ip_gtpc := "127.0.23.1"
+GGSN_Tests.m_ggsn_ip_gtpu := "127.0.23.1"
 
 [EXECUTE]
-GGSN_Tests.TC_dummy
+#GGSN_Tests.TC_dummy
 GGSN_Tests.TC_pdp4_act_deact
 GGSN_Tests.TC_pdp4_act_deact_ipcp
 GGSN_Tests.TC_pdp4_act_deact_pcodns
@@ -28,6 +27,3 @@
 GGSN_Tests.TC_pdp6_act_deact_icmp6
 
 GGSN_Tests.TC_echo_req_resp
-
-GGSN_Tests.TC_pdp4_act_deact_ipcp_udp
-