typo

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49864 b456876b-0849-0410-b77d-98878d47e9d5
[FIX] Module top_articles: allow intended sorting by number of reads to work for this module. The top articles module was sorting by ascending article ID instead.

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@49865 b456876b-0849-0410-b77d-98878d47e9d5