net/ftp.rb: NullSocket#closed?
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53810 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
net/ftp.rb: NullSocket#closed?
connection. [Fix GH-1232]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53810 b2dd03c8-39d4-4d8f-98ff-823fe69b080e