Log Message:
Update rubygems pacakge to 1.2.0.

Release 1.2.0 adds new features and fixes some bugs.

New features:

* RubyGems no longer performs bulk updates and instead only fetches the gemspec
  files it needs.  Alternate sources will need to upgrade to RubyGems 1.2 to
  allow RubyGems to take advantage of the new metadata updater.  If a pre 1.2
  remote source is in the sources list, RubyGems will revert to the bulk update
  code for compatibility.
* RubyGems now has runtime and development dependency types.  Use
  #add_development_dependency and #add_runtime_dependency.  All typeless
  dependencies are considered to be runtime dependencies.
* RubyGems will now require rubygems/defaults/operating_system.rb and
  rubygems/defaults/#{RBX_ENGINE}.rb if they exist.  This allows packagers and
  ruby implementers to add custom behavior to RubyGems via these files.  (If
  the RubyGems API is insufficient, please suggest improvements via the
  RubyGems list.)
* /etc/gemrc (and windows equivalent) for global settings
* setup.rb now handles --vendor and --destdir for packagers
* `gem stale` command that lists gems by last access time

Bugs Fixed:

* File modes from gems are now honored, patch #19737
* Marshal Gem::Specification objects from the future can now be loaded.
* A trailing / is now added to remote sources when missing, bug #20134
* Gems with legacy platforms will now be correctly uninstalled, patch #19877
* `gem install --no-wrappers` followed by `gem install --wrappers` no longer
  overwrites executables
* `gem pristine` now forces reinstallation of gems, bug #20387
* RubyGems gracefully handles ^C while loading .gemspec files from disk, bug
  #20523
* Paths are expanded in more places, bug #19317, bug #19896
* Gem::DependencyInstaller resets installed gems every install, bug #19444
* Gem.default_path is now honored if GEM_PATH is not set, patch #19502

Other Changes Include:

* setup.rb
  * stub files created by RubyGems 0.7.x and older are no longer removed.  When
    upgrading from these ancient versions, upgrade to 1.1.x first to clean up
    stubs.
  * RDoc is no longer required until necessary, patch #20414
* `gem server`
  * Now completely matches the output of `gem generate_index` and
    has correct content types
  * Refreshes from source directories for every hit.  The server will no longer
    need to be restarted after installing gems.
* `gem query --details` and friends now display author, homepage, rubyforge url
  and installed location
* `gem install` without -i no longer reinstalls dependencies if they are in
  GEM_PATH but not in GEM_HOME
* Gem::RemoteFetcher now performs persistent connections for HEAD requests,
  bug #7973