title: Django Queryset access by index issue
body: <p>I have a Client model with a created_at field. I want to update the created_at for a client from the shell. I did the following:</p>
  
  <pre><code>&gt;&gt;&gt; c = Client.objects.all()
  &gt;&gt;&gt; c[1].created_at
  &gt;&gt;&gt; # I get nothing here since it's not set yet
  &gt;&gt;&gt; from django.utils import timezone
  &gt;&gt;&gt; c[1].created_at = timezone.now()
  &gt;&gt;&gt; c[1].save()
  &gt;&gt;&gt; c[1].created_at
  &gt;&gt;&gt; # I still get nothing here. Even when I reload the queryset, I get nothing.
  </code></pre>
  
  <p>However, when I do the same thing with <code>c = Client.object.get(id=1)</code>, it works. Why does this happen? </p>