[Bug #14866][ruby-core:87602]

  https://github.com/ruby/webrick/pull/10



Co-authored-by: TSUYUSATO Kitsune <make.just.on@gmail.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64216 b2dd03c8-39d4-4d8f-98ff-823fe69b080e