level -> label (mochajs#3477)

As noted by @plroebuck `level` is not used, should be `label` instead.

mochajs@37193a4#commitcomment-30530038

Author: Bamieh

browser-entry.js

@@ -7,7 +7,7 @@
  * Shim process.stdout.
  */
 
-process.stdout = require('browser-stdout')({level: false});
+process.stdout = require('browser-stdout')({label: false});
 
 var Mocha = require('./lib/mocha');