title: Django 1.4 - django.db.models.FileField.save(filename, file, save=True) produces error with non-ascii filename
body: <p>I'm making a fileupload feature using django.db.models.FileField of Django 1.4</p>
  
  <p>When I try to upload a file whose name includes non-ascii characters, it produces error below.</p>
  
  <blockquote>
    <p>'ascii' codec can't encode characters in position 109-115: ordinal not
    in range(128)</p>
  </blockquote>
  
  <p>The actual code is like below</p>
  
  <blockquote>
    <p>file = models.FileField(_("file"),
                            max_length=512,
                            upload_to=os.path.join('uploaded', 'files', '%Y', '%m', '%d'))</p>
    
    <p>file.save(filename, file, save=True)  <strong>#&lt;- This line produces the error
    above, if 'filename' includes non-ascii character</strong></p>
  </blockquote>
  
  <p>If I try to use <code>unicode(filename, 'utf-8')</code> insteadof <code>filename</code>, it produces error below</p>
  
  <blockquote>
    <p>TypeError: decoding Unicode is not supported</p>
  </blockquote>
  
  <p>How can I upload a file whose name has non-ascii characters?</p>
  
  <p>Info of my environment:</p>
  
  <blockquote>
    <p>sys.getdefaultencoding() : 'ascii'</p>
    
    <p>sys.getfilesystemencoding() : 'UTF-8'</p>
    
    <p>using Django-1.4.10-py2.7.egg</p>
  </blockquote>