Updated rubygems to 2.4.5.

RubyGems 2.4.5 installed

=== 2.4.5 / 2014-12-03

Bug fixes:

* Improved speed of requiring gems.  (Around 25% for a 60 gem test).  Pull
  request #1060 by unak.
* RubyGems no longer attempts to look up gems remotely with the --local flag.
  Pull request #1084 by Jeremy Evans.
* Executable stubs use the correct gem version when RUBYGEMS_GEMDEPS is
  active.  Issue #1072 by Michael Kaiser-Nyman.
* Fixed handling of pinned gems in lockfiles with versions.  Issue #1078 by
  Ian Ker-Seymer.
* Fixed handling of git@example:gem.git URIs.  Issue #1054 by Mogutan Mogu.
* Fixed handling of platforms retrieved from the dependencies API.  Issue
  #1058 and patch suggestion by tux-mind.
* RubyGems now suggests a copy-pasteable `gem pristine` command when
  extensions are missing.  Pull request #1057 by Shannon Skipper.
* Improved errors for long file names when packaging.  Pull request #1016 by
  Piotrek Bator.
* `gem pristine` now skips gems cannot be found remotely.  Pull request #1064
  by Tuomas Kareinen.
* `gem pristine` now caches gems to the proper directory.  Pull request #1064
  by Tuomas Kareinen.
* `gem pristine` now skips bundled gems properly.  Pull request #1064 by
  Tuomas Kareinen.
* Improved interoperability of Vagrant with RubyGems.  Pull request #1057 by
  Vít Ondruch.
* Renamed CONTRIBUTING to CONTRIBUTING.rdoc to allow markup.  Pull request
  #1090 by Roberto Miranda.
* Switched from #partition to #reject as only one collection is used.  Pull
  request #1074 by Tuomas Kareinen.
* Fixed installation of gems on systems using memory-mapped files.  Pull
  request #1038 by Justin Li.
* Fixed bug in Gem::Text#min3 where `a == b < c`.  Pull request #1026 by
  fortissimo1997.
* Fixed uninitialized variable warning in BasicSpecification.  Pull request
  #1019 by Piotr Szotkowski.
* Removed unneeded exception handling for cyclic dependencies.  Pull request
  #1043 by Jens Wille.
* Fixed grouped expression warning.  Pull request #1081 by André Arko.
* Fixed handling of platforms when writing lockfiles.

=== 2.4.4 / 2014-11-12
Fixed building with gcc 4.6.3. Fixes #3235.
Vendored libyaml 0.1.5 (again).
Added configure options for vendored libyaml.
Use bundler 1.7.9.
Bumped daedalus-core.
Try apt-get update on Travis Linux.
Su effen do.
Macro for cleaning up RBX_DTRACE_CONST char* usage

This has been extracted from https://github.com/rubinius/rubinius/pull/3214
base on feedback from @brixen.
Updated CI specs to RubySpec 07d5b741.
Updated MSpec source to b437013f.
Updated CI tags.
Fix SystemCallError.new to pass new rubyspecs
Fixes #3243
Remove UnsupportedLibraryError
This was an artifact from when Rubinius didn't support the 'mathn' library
and was checked for in the mspec test suite to detect an unsupported library.
This shouldn't be necessary in Rubinius anymore.
Add failing spec for Thread#join coercing timeout to Float
Fix Thread#join timeout coercion to Float and handling of nil
Fixes #3106
Added spec for reopen with path closing fd.
Fixed IO#reopen with path.
Revert "Avoid caching singleton classes."

This reverts commit 977fe2ee0994836a0dbfb3e9c6c2f512cd7a2e94.
Revert "Singleton classes can't have subclasses."

This reverts commit f7e4f42b62404b71f7f18e24195a8bd15983b4e9.