Fill cloud interface server side

Fix https://github.com/GNS3/gns3-gui/issues/1535

tests/compute/builtin/nodes/test_nat.py

@@ -32,7 +32,7 @@ def test_json(on_gns3vm, project):
         "ports_mapping": [
             {
                 "interface": "virbr0",
-                "name": "virbr0",
+                "name": "nat0",
                 "port_number": 0,
                 "type": "ethernet"
             }