Fix conversion issue for old IOU projects

Fix https://github.com/GNS3/gns3-gui/issues/1868

gns3server/controller/topology.py

@@ -331,6 +331,14 @@ def _convert_1_3_later(topo, topo_path):
                 node["symbol"] = ":/symbols/vbox_guest.svg"
         elif old_node["type"] == "IOUDevice":
             node["node_type"] = "iou"
+            node["port_name_format"] = old_node.get("port_name_format", "Ethernet{segment0}/{port0}")
+            node["port_segment_size"] = int(old_node.get("port_segment_size", "4"))
+            if node["symbol"] is None:
+                if "l2" in node["properties"].get("path", ""):
+                    node["symbol"] = ":/symbols/multilayer_switch.svg"
+                else:
+                    node["symbol"] = ":/symbols/router.svg"
+
         elif old_node["type"] == "Cloud":
             old_node["ports"] = _create_cloud(node, old_node, ":/symbols/cloud.svg")
         elif old_node["type"] == "Host":

tests/topologies/1_5_iou/after/1_5_iou.gns3

@@ -30,8 +30,8 @@
                 "name": "IOU1",
                 "node_id": "aaeb2288-a7d8-42a9-b9d8-c42ab464a390",
                 "node_type": "iou",
-                "port_name_format": "Ethernet{0}",
-                "port_segment_size": 0,
+                "port_name_format": "Ethernet{segment0}/{port0}",
+                "port_segment_size": 4,
                 "first_port_name": null,
                 "properties": {
                     "ethernet_adapters": 2,