Removed some references to django.contrib.comments which has been removed.

Author: timgraham

docs/ref/contrib/sites.txt

@@ -404,12 +404,6 @@ Here's how Django uses the sites framework:
  redirect object is associated with a particular site. When Django searches
  for a redirect, it takes into account the current site.
 
-* In the comments framework, each comment is associated with a particular
- site. When a comment is posted, its
- :class:`~django.contrib.sites.models.Site` is set to the current site,
- and when comments are listed via the appropriate template tag, only the
- comments for the current site are displayed.
-
 * In the :mod:`flatpages framework <django.contrib.flatpages>`, each
  flatpage is associated with a particular site. When a flatpage is created,
  you specify its :class:`~django.contrib.sites.models.Site`, and the

docs/topics/db/multi-db.txt

@@ -675,8 +675,8 @@ how you can split these models across databases:
 - ``auth`` models — ``User``, ``Group`` and ``Permission`` — are linked
  together and linked to ``ContentType``, so they must be stored in the same
  database as ``ContentType``.
-- ``admin`` and ``comments`` depend on ``auth``, so their models must be in
- the same database as ``auth``.
+- ``admin`` depends on ``auth``, so their models must be in the same database
+ as ``auth``.
 - ``flatpages`` and ``redirects`` depend on ``sites``, so their models must be
  in the same database as ``sites``.