Corrected an inconsistency in the documentation regarding the way to specify...

Corrected an inconsistency in the documentation regarding the way to specify the locmem and dummy cache backend. Thanks to Jens Diemer for the report.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@11750 bcc190cf-cafb-0310-a4f2-bffc1f526a37