title: Django restricting certain keywords?
body: <p>I got into this issue that i'm unable to resolve somehow.</p>
  
  <p>So i'm running on Django 1.7.7 with two apps, models as follows</p>
  
  <ul>
  <li>order.Order </li>
  <li><p>order.OrderItinerary (m2m through table)</p></li>
  <li><p>itinerary.Itinerary</p></li>
  <li>itinerary.Photo</li>
  </ul>
  
  <p>The problem here is that when i use foreign key inside OrderItinerary that points to Itinerary model, it works.
  But when foreign key from Photo points to Itinerary model it raises me this error</p>
  
  <pre><code>&lt;class 'itinerary.admin.ItineraryPhotoAdmin'&gt;: (admin.E108) The value of 'list_display[1]' refers to 'itinerary', which is not a callable, an attribute of 'ItineraryPhotoAdmin', or an attribute or method on 'itinerary.Photo'.
  </code></pre>
  
  <p>i just don't get how two distinct models pointing to the same model could give me different results</p>
  
  <pre><code>class Order(GenericModel):
  def __str__(self):
      return "%s" %(self.title)
  
  title       = models.CharField(max_length=64)
  description = models.TextField(blank=True)
  order_number= models.CharField(max_length=64, unique=True, blank=True, default='')
  itineraries = models.ManyToManyField('itinerary.Itinerary', through='order.OrderItinerary')
  </code></pre>
  
  <p>Second Model</p>
  
  <pre><code>class OrderItinerary(GenericModel):
  title       = models.CharField(max_length=64)
  description = models.TextField(blank=True)
  rating      = models.FloatField(blank=True)
  order       = models.ForeignKey('order.Order')
  itinerary   = models.ForeignKey('itinerary.Itinerary')
  </code></pre>
  
  <p>Third Model</p>
  
  <pre><code>class Itinerary(GenericModel):
  uuid        = models.CharField(max_length=128, default=generate_uuid)
  title       = models.CharField(max_length=64)
  description = models.TextField(blank=True)
  price       = models.DecimalField(blank=True, null=True, decimal_places=2, max_digits=5)
  total_rating= models.FloatField(default=0)
  rating_num  = models.IntegerField(default=0, verbose_name="number of customers rated")
  </code></pre>
  
  <p>Fourth Model</p>
  
  <pre><code>class Photo(GenericModel):
  caption     = models.CharField(max_length=254, default='', blank=True)
  photo       = models.ImageField(upload_to=generate_photo_name)
  itinenary   = models.ForeignKey('itinerary.Itinerary', related_name="itinerary_photo")
  </code></pre>