RubyGems 1.8.0 to 1.8.4
RubyGems [>= 1.8.0, < 1.8.5] has a bug that changes Gem.dir whenever you call Gem::Installer#install with an :install_dir set. We have to change it back for our sudo mode to work.
# File bundler/rubygems_integration.rb, line 707 def preserve_paths old_dir = gem_dir old_path = gem_path yield Gem.use_paths(old_dir, old_path) end