[1.1.X] Fixed #12476 -- Forced the rollout of generators passed to SortedDict...

[1.1.X] 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.

Backport of r12064 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12065 bcc190cf-cafb-0310-a4f2-bffc1f526a37