Fix test failure of binmode from r40879

http://ruby-mswin.cloudapp.net/vc10-x64/ruby-trunk/log/20130521T131601Z.log.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40892 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Add NEWS for r40879: Digest::Class.file

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40893 b2dd03c8-39d4-4d8f-98ff-823fe69b080e