We only clear ordering when doing so cannot change the result returned by
the get() method i.e.  when the query does not already define limits.

Thanks to mattdennewitz@gmail.com for the report, and jdunck for the patch



git-svn-id: http://code.djangoproject.com/svn/django/trunk@11916 bcc190cf-cafb-0310-a4f2-bffc1f526a37