Fixed #12476 -- Forced the rollout of generators passed to SortedDict so that...

Fixed #12476 -- Forced the rollout of generators passed to SortedDict so that the data source can be read twice. Thanks to gsf for the report, and Alex for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12064 bcc190cf-cafb-0310-a4f2-bffc1f526a37