server: retrieve remote IP address properly

It seems that the IP address shouldn't be retrieved from handshake but
from request. This would be easier if there was any documentation
instead of random StackOverflow questions.

lib/api/socketio/displays.js

@@ -12,7 +12,9 @@ var _ = require('lodash'),
 // Handle newly arrived clients
 function handleNewDisplay(io) {
   io.on('connection', function(socket) {
-    logger.info('new display', socket.handshake.address);
+    var ip = (socket.handshake.headers || {})['x-forwarded-for'] ||
+          socket.request.connection.remoteAddress;
+    logger.info('new display', ip);
     socket.on('register', function(data, fn) {
 
       // Handle registration, retrieve the display name or generate a new one.
@@ -36,9 +38,7 @@ function handleNewDisplay(io) {
         .then(function(display) {
           var name = display.toJSON().name,
               group = display.toJSON().group,
-              viewport = display.toJSON().viewport,
-              ip = (socket.handshake.headers || {})['x-forwarded-for'] ||
-                (socket.handshake.address || {}).address;
+              viewport = display.toJSON().viewport;
 
           logger.info('registered display', name, ip);
           display