[FIX] delete all anon ratings

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/13.x@52629 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] check for "0", don't set

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/13.x@52630 b456876b-0849-0410-b77d-98878d47e9d5