[rubygems/rubygems] Add a package attr_reader to Gem::Installer.
Add some basic specs for the package attr_reader.
https://github.com/rubygems/rubygems/commit/68af2a0ee3
[rubygems/rubygems] Add a package attr_reader to Gem::Installer.
Add some basic specs for the package attr_reader.
https://github.com/rubygems/rubygems/commit/68af2a0ee3