[1.1.X] Fixed #11535: Corrected SQL generated for queries involving generic...

[1.1.X] Fixed #11535: Corrected SQL generated for queries involving generic relations and ORed Q objects. Thanks to brianglass for report, tobias for fix and test, and Alex for review. 

r12405 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12406 bcc190cf-cafb-0310-a4f2-bffc1f526a37