S1AP_Emulation: initialize comp_ref member of S1apAssociationTable

The comp_ref member in S1apAssociationTable is not initialized. When an
item is delted from the S1apAssociationTable, comp_ref is set to null.
Let's maintain a consistent state and also set comp_ref to null when the
table is initialized.

Related: OS#5760
Change-Id: If86a18a4a953665c1e2bf7f757880ba3ac6c0f83
diff --git a/library/S1AP_Emulation.ttcn b/library/S1AP_Emulation.ttcn
index 9b159d4..38c738b 100644
--- a/library/S1AP_Emulation.ttcn
+++ b/library/S1AP_Emulation.ttcn
@@ -274,6 +274,7 @@
 		S1apAssociationTable[i].cgi := omit;
 		S1apAssociationTable[i].tai := omit;
 		S1apAssociationTable[i].nus := valueof(t_NAS_UE_State(g_pars.role));
+		S1apAssociationTable[i].comp_ref := null;
 	}
 }