Fixed #6748 -- When printing the repr() of querysets, don't load or display

more than 20 objects.

This means that accidentally executing HugeStoryArchive.objects.all() at the
interactive prompt (or in the debug template) won't try to load all 4,233,010
stories into memory and print them out. That would previously cause resource
starvation and other "interesting" crashes.

If you really, really want the previous behaviour (e.g. in a doctest that
prints more than 20 items), display "list(qs)" instead of just "qs".


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9202 bcc190cf-cafb-0310-a4f2-bffc1f526a37