networkInterfaceDefault() fix windows

lib/network.js

@@ -28,7 +28,7 @@ const _openbsd = (_platform === 'openbsd');
 const _sunos = (_platform === 'sunos');
 
 let _network = {};
-let _default_iface;
+let _default_iface = '';
 let _ifaces = [];
 let _networkInterfaces = [];
 let _mac = {};
@@ -38,19 +38,25 @@ function getDefaultNetworkInterface() {
 
   let ifaces = os.networkInterfaces();
   let ifacename = '';
+  let ifacenameFirst = '';
+
   let scopeid = 9999;
 
   // fallback - "first" external interface (sorted by scopeid)
   for (let dev in ifaces) {
     if (ifaces.hasOwnProperty(dev)) {
       ifaces[dev].forEach(function (details) {
-        if (details && details.internal === false && details.scopeid && details.scopeid < scopeid) {
-          ifacename = dev;
-          scopeid = details.scopeid;
+        if (details && details.internal === false) {
+          ifacenameFirst = ifacenameFirst || dev; // fallback if no scopeid
+          if (details.scopeid && details.scopeid < scopeid) {
+            ifacename = dev;
+            scopeid = details.scopeid;
+          }
         }
       });
     }
   }
+  ifacename = ifacename || ifacenameFirst || '';
   if (_linux || _darwin || _freebsd || _openbsd || _sunos) {
     let cmd = '';
     if (_linux) cmd = 'route 2>/dev/null | grep default | awk \'{print $8}\'';