rails/rails — pull request #12530 by vipulnsward (2013-10-14 16:26:40+00:00)
Title: `$SAFE = 4;` has been removed with Ruby 2.1

`$SAFE = 4;` has been deprecated with Ruby 2.1
For background -
https://bugs.ruby-lang.org/issues/8468
Changset - https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/41259/diff/test/ruby/test_thread.rb