Fix short label diplay instead of custom interface labels

Fix https://github.com/GNS3/gns3-gui/issues/1742, https://github.com/GNS3/gns3-gui/issues/1752

gns3server/controller/ports/port.py

@@ -50,6 +50,9 @@ class Port:
 
     @property
     def short_name(self):
+        # If port name format has change we use the port name as the short name (1.X behavior)
+        if not self._name.startswith(self.long_name_type()):
+            return self._name
         return self.short_name_type + "{}/{}".format(self._interface_number, self._port_number)
 
     def __json__(self):

tests/controller/test_port.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2016 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from gns3server.controller.ports.ethernet_port import EthernetPort
+
+
+def test_short_name():
+    # If no customization of port name format return the default short name
+    assert EthernetPort("Ethernet0", 0, 0, 0).short_name == "e0/0"
+    # If port name format has change we use the port name as the short name (1.X behavior)
+    assert EthernetPort("eth0", 0, 0, 0).short_name == "eth0"