Fixed #16786 -- Minor cleanups in the memcached section of the caching topic...

Fixed #16786 -- Minor cleanups in the memcached section of the caching topic guide. Thanks to jamesp for the report and patch.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@16748 bcc190cf-cafb-0310-a4f2-bffc1f526a37