7814 breaks FileField.save_file for related objects

[oggy]

class Article(models.Model):
    body = models.CharField(max_length=200)
    class Admin:
        pass

class Attachment(models.Model):
    article = models.ForeignKey(Article, num_in_admin=1, num_extra_on_change=1, edit_inline=models.TABULAR)
    file = models.FileField(upload_to='uploads/attachments/%Y/%m/%d')
    keep = models.BooleanField(core=True, default=True, editable=False)
    remove = models.BooleanField(default=False)
    name = models.CharField(max_length=30)

Django admin breaks when attempting to create a new Article w/o any attachments. The problem is that after the introduction of MultiPartParser in 7814, request.POST contains an entry
u'attachment.0.file_file': [u'']
whereas that entry would be missing in prior revisions. This eventually leads to an entry of:
u'file_file': [u'']
instead of
u'file_file': []
in the new_data dict which is passed as the parameter to FileField.save_file, so this method eventually breaks. The fix is simple and I'm attaching a patch for it. The only thing is that I'm not sure if it would perhaps be better to handle this somewhere else?

[Marty Alchin]

I'll also be looking at this from the side of the impending filestorage refactor, so I'm also marking it fs-rf for now.

[Jacob]

(In [7906]) Fixed #7667: fixied FileField.save_file for inline related objects. This is really just papering over a bigger problem that should get fixed either by newforms-admin or the file-storage refactoring, but this fix makes the admin work until either of those things happen. Thanks, oggy.