The change to lib/rubygems/package.rb is a critical bug fix for RubyGems signing support. Without this fix users of the LowSecurity policy will not be able to install signed gems.
The change to lib/rubygems/package/old.rb is not a critical bug fix. It will make my diagnosis of problems in RubyGems easier, though. It does not change operation of RubyGems in Ruby 2.0.0.
The change to lib/rubygems/package/old.rb is not critical. It suppresses a warning almost nobody will ever see and fixes behavior on 1.8.7. These are not sufficient for inclusion.
The change to lib/rubygems/package.rb is critical. Without it users will not be able to install signed gems built with rubygems 2.0 or newer on ruby 2.0.0 without upgrading rubygems.