[1.3.X] Clarified deployment docs to avoid giving users the impression that...

[1.3.X] Clarified deployment docs to avoid giving users the impression that staticfiles should be used to actually serve files in production.

Backport of r17338 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.3.X@17339 bcc190cf-cafb-0310-a4f2-bffc1f526a37