title: Translations of QMessageBox not work in Qt5.3
body: <p>I'm a fan of Qt and update it frequently, Qt5.1->5.2->5.3.</p>
  
  <p>However, the tranalations of Standard buttons like "Ok" "Cancel" "Save" do not work anymore in Qt5.3.
  They are not translated, but just plain English.</p>
  
  <p>The Code for translations does <strong>NOT</strong> change through each version of Qt.
  like:</p>
  
  <pre><code>TRANSLATIONS = qt_fr.ts
  QTranslator trans
  trans.load("qt_fr");
  a.installTranslator(&amp;trans);
  </code></pre>
  
  <p>any idea?</p>
  
  <p><strong>[Update]</strong>
  AFAIN, it might be a bug. Go back to Qt5.1 is a slution if U dont have to use some improvements in new Qts.</p>