title: Can't display DateField on form with auto_now = True
body: <p>I have a model with auto_now, and auto_now_add set for Update and Create fields:</p>
  
  <pre><code>class HotelProfiles(models.Model):
    fe_result_id = models.AutoField(primary_key=True)
    fe_created_date = models.DateTimeField(verbose_name='Created',
                                           blank=True,
                                           auto_now_add=True)
    fe_updated_date = models.DateTimeField(verbose_name='Updated',
                                           blank=True, 
                                           auto_now=True)
  </code></pre>
  
  <p>In the Admin it displays both fields but leaves them uneditable.  They
  don't seem to be passed to my form to be rendered.  I don't want them
  to be editable, but I would like to display at the top of my form.
  How can I do this?</p>
  
  <p>This is in my HotelProfilesAdmin class:</p>
  
  <pre><code>readonly_fields = ('fe_result_id', 'fe_created_date', 'fe_updated_date', 'fe_owner_uid')
  #date_hierarchy = 'lto_end_date' 
  fieldsets = (
      ("Internal Use Only", {
          'classes': ('collapse',),
          'fields': ('fe_result_id', 'fe_created_date', 'fe_owner_uid', 'fe_updated_date', 'fe_result_status')
      }),
  </code></pre>