merge revision(s) 60149: [Backport #14003]
Merge rubygems-2.6.14 changes. It fixed http://blog.rubygems.org/2017/10/09/unsafe-object-deserialization-vulnerability.html
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@61244 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 60149: [Backport #14003]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@61244 b2dd03c8-39d4-4d8f-98ff-823fe69b080e