Log Message:
Update rubygems to 2.0.8.

This includes a fix for CVE-2013-4287 in rubygems.

=== 2.0.8 / 2013-09-09

Security fixes:

* RubyGems 2.0.7 and earlier are vulnerable to excessive CPU usage due to a
  backtracking in Gem::Version validation.  See CVE-2013-4287 for full details
  including vulnerable APIs.  Fixed versions include 2.0.8, 1.8.26 and
  1.8.23.1 (for Ruby 1.9.3).  Issue #626 by Damir Sharipov.

Bug fixes:

* Fixed Gem.clear_paths when Security is defined at top-level.  Pull request
  #625 by elarkin

=== 2.0.7 / 2013-08-15

* Extensions may now be built in parallel (therefore gems may be installed in
  parallel).  Bug #607 by Hemant Kumar.
* Changed broken link to RubyGems Bookshelf to point to RubyGems guides.  Ruby
  pull request #369 by 謝致邦.
* Fixed various test failures due to platform differences or poor tests.
  Patches by Yui Naruse and Koichi Sasada.
* Fixed documentation for Kernel#require.

=== 2.0.6 / 2013-07-24

Bug fixes:

* Fixed the `--no-install` and `-I` options to `gem list` and friends.  Bug
  #593 by Blargel.
* Fixed crash when installing gems with extensions under the `-V` flag.  Bug
  #601 by Nick Hoffman.
* Fixed race condition retrieving HTTP connections in Gem::Request on JRuby.
  Bug #597 by Hemant Kumar.
* Fixed building extensions on ruby 1.9.3 under mingw.  Bug #594 by jonforums,
  Bug #599 by Chris Riesbeck
* Restored default of remote search to `gem search`.

=== 2.0.5 / 2013-07-11

Bug fixes:

* Fixed building of extensions that run ruby in their makefiles.  Bug #589 by
  Zachary Salzbank.
=== 2.0.4 / 2013-07-09

Bug fixes:

* Fixed error caused by gem install not finding the right platform for your
  platform. Bug #576 by John Anderson
* Fixed pushing gems with the default host.  Bug #495 by Utkarsh Kukreti
* Improved unhelpful error message from `gem owner --remove`.  Bug #488 by
  Steve Klabnik
* Fixed typo in `gem spec` help.  Pull request #563 by oooooooo
* Fixed creation of build_info with --install-dir.  Bug #457 by Vít Ondruch.
* RubyGems converts non-string dependency names to strings now.  Bug #505 by
  Terence Lee
* Outdated prerelease versions are now listed in `gem outdated`.
* RubyGems now only calls fsync() on the specification when installing, not
  every file from the gem.  This improves the performance of gem installation
  on some systems.  Pull Request #556 by Grzesiek Kolodziejczyk
* Removed surprise search term anchoring in `gem search` to restore 1.8-like
  search behavior while still defaulting to --remote.  Pull request #562 by
  Ben Bleything
* Fixed handling of DESTDIR when building extensions.  Pull request #573 by
  Akinori MUSHA
* Fixed documentation of `gem pristine` defaults (--all is not a default).
  Pull request #577 by Shannon Skipper
* Fixed a windows extension-building test failure.  Pull request #575 by
  Hiroshi Shirosaki
* Fixed issue with `gem update` where it would attempt to use a Version
  instead of a Requirement to find the latest gem.  Fixes #570 by Nick Cox.
* RubyGems now ignores an empty but set RUBYGEMS_HOST environment variable.
  Based on pull request #558 by Robin Dupret.
* Removed duplicate creation of gem subdirectories in
  Gem::DependencyInstaller.  Pull Request #456 by Vít Ondruch
* RubyGems now works with Ruby built with `--with-ruby-version=''`.  Pull
  Request #455 by Vít Ondruch
* Fixed race condition when two threads require the same gem.  Ruby bug report
  #8374 by Joel VanderWerf
* Cleaned up siteconf between extension build and extension install.  Pull
  request #587 by Dominic Cleal
* Fix deprecation warnings when converting gemspecs to yaml.  Ruby commit
  r41148 by Yui Naruse