partially revert r41163 because r41173 didn't fix failure

http://ruby-mswin.cloudapp.net/vc10-x64/ruby-trunk/log/20130608T101707Z.log.html.gz

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41179 b2dd03c8-39d4-4d8f-98ff-823fe69b080e