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