[1.2.X] Fixed #15283 -- Made a minor performance tweak to __iter__. Thanks to lanyjie for the report.

Backport of r15491 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15496 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -79,7 +79,7 @@ class QuerySet(object):
             else:
                 self._result_cache = list(self.iterator())
         elif self._iter:
-            self._result_cache.extend(list(self._iter))
+            self._result_cache.extend(self._iter)
         return len(self._result_cache)
 
     def __iter__(self):