Fixed #7260 -- Corrected the description of the exception returned by get()...

Fixed #7260 -- Corrected the description of the exception returned by get() when multiple objects match the search criteria. Thanks, leotr.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7559 bcc190cf-cafb-0310-a4f2-bffc1f526a37