chore(travis): use ports proxied by SauceLabs

Some browser does not allow to proxy localhost and so SL uses another proxy on the VM. This proxy only proxies some ports (SauceConnect proxies all ports).

This is the issue why Safari didn't connect for e2e tests, because 9877 was not proxied.

This change makes sure we use SL enabled ports.

Author: vojtajina

lib/grunt/utils.js

@@ -253,7 +253,7 @@ module.exports = {
       stream: options && options.stream
     };
 
-    args.push('--port=' + this.lastParallelTaskPort);
+    args.push('--port=' + this.sauceLabsAvailablePorts.pop());
 
     if (args.indexOf('test:e2e') !== -1 && grunt.option('e2e-browsers')) {
       args.push('--browsers=' + grunt.option('e2e-browsers'));
@@ -265,10 +265,9 @@ module.exports = {
       args.push('--reporters=' + grunt.option('reporters'));
     }
 
-    this.lastParallelTaskPort++;
-
     return task;
   },
 
-  lastParallelTaskPort: 9876
+  // see http://saucelabs.com/docs/connect#localhost
+  sauceLabsAvailablePorts: [9000, 9001, 9080, 9090, 9876]
 };