title: How set set title to leftBarButtonItem
body: <p>I have <strong>root</strong> ViewController and <strong>detailed</strong> ViewController. When i push to detailedViewController i get leftBarButtonItem with the title from the root one. But i want the title to be just "Back", nothing more. So how to do that?</p>
  
  <p>This doesn't help</p>
  
  <pre><code>self.navigationItem.leftBarButtonItem.title = @"Back";
  </code></pre>
  
  <p>To create my on type barButtonItem(for example 104 with left arrow) and to set it to leftBarButtonItem is terrible decision.</p>
  
  <p>Is there other way than to change the title of the rootViewController manually before pushing?</p>