Interface starting with gns3 are not display by default in the cloud

Fix https://github.com/GNS3/gns3-gui/issues/2199

gns3server/utils/interfaces.py

@@ -240,7 +240,9 @@ def interfaces():
     # This interface have special behavior
     for result in results:
         result["special"] = False
-        for special_interface in ("lo", "vmnet", "vboxnet", "docker", "lxcbr", "virbr", "ovs-system", "veth", "fw", "p2p", "bridge", "vmware", "virtualbox"):
+        for special_interface in ("lo", "vmnet", "vboxnet", "docker", "lxcbr",
+                                  "virbr", "ovs-system", "veth", "fw", "p2p",
+                                  "bridge", "vmware", "virtualbox", "gns3"):
             if result["name"].lower().startswith(special_interface):
                 result["special"] = True
         for special_interface in ("-nic"):