fix example for script.runInContext

[jalexanderfox]

object literal stored in sandbox was throwing an error, vm.createContext(sandbox); returns a contextifiedSandbox which was not being used in script.runInContext(sandbox);

This modification fixes the example by creating the context and passing it as a parameter to script.runInContext

[jasnell]

This is not necessary. The contextifiedSandbox returned by the createContext method is the exact same sandbox object that is passed in. You can verify that by doing a quick:

var vm = require('vm');
var sandbox = {};
console.log(sandbox === vm.createContext(sandbox));

[jalexanderfox]

Same as #25566, I was using an old version of node 0.10.35_2, my apologies.

[jasnell]

No need to apologize! PR's are always welcome!