Fixed #16528 - Documented test runner returns 1, regardless of the number of...

Fixed #16528 - Documented test runner returns 1, regardless of the number of test failures; thanks teraom.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16584 bcc190cf-cafb-0310-a4f2-bffc1f526a37