title: How to disable importing authtoken.models when using SessionAuthentication with django-rest-framework?
body: <p>In my rest_framework settings I set SessionAuthentication as the default authentication class</p>
  
  <pre><code>'DEFAULT_AUTHENTICATION_CLASSES': (
      'rest_framework.authentication.SessionAuthentication',
  )
  </code></pre>
  
  <p>The problem is that my User DELETE api view tries to collapse delete on the authtoken_token table, which doesn't exist (since I don't need it), raising a database exception.</p>
  
  <p>Specifically, when obj.delete() is invoked in DestroyModelMixin.destroy, this exception is raised:</p>
  
  <pre><code>DatabaseError: relation "authtoken_token" does not exist
  LINE 1: ...oken"."user_id", "authtoken_token"."created" FROM "authtoken...
  </code></pre>
  
  <p>Is one required to syncdb rest_framework's models, even if one doesn't need them?</p>
  
  <p>Is there a way to use SessionAuthentication without including authtoken.models?</p>
  
  <p>Am I doing something wrong?</p>
  
  <p>(removing authtoken.models.Token completely from rest_framework/authentication.py seems to solve the problem)</p>