Initial Open5GS support

Change-Id: Iff8b88dc22d8f156572839abb48b0c1377c55e33
diff --git a/src/osmo_gsm_tester/obj/epc.py b/src/osmo_gsm_tester/obj/epc.py
index aaa96b7..4c43f5e 100644
--- a/src/osmo_gsm_tester/obj/epc.py
+++ b/src/osmo_gsm_tester/obj/epc.py
@@ -71,6 +71,9 @@
         elif epc_type == 'srsepc':
             from .epc_srs import srsEPC
             epc_class = srsEPC
+        elif epc_type == 'open5gsepc':
+            from .epc_open5gs import Open5gsEPC
+            epc_class = Open5gsEPC
         else:
             raise log.Error('EPC type not supported:', epc_type)