wait until the shutdowning message reaches to the server
see #8831
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42838 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
wait until the shutdowning message reaches to the server
see #8831
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42838 b2dd03c8-39d4-4d8f-98ff-823fe69b080e