Update ruby193-base to 1.9.3p286.

Ruby 1.9.3-p286 is released.

This release includes some security fixes, and other many bug fixes.

* $SAFE escaping vulnerability about Exception#to_s / NameError#to_s
  (CVE-2012-4464, CVE-2012-4466)
* Unintentional file creation caused by inserting a illegal NUL character
* other many bug fixes.

See ticktes and ChangeLog for details.

Changelog: http://svn.ruby-lang.org/repos/ruby/tags/v1_9_3_286/ChangeLog
tickets: https://bugs.ruby-lang.org/projects/ruby-193/issues?set_filter=1&status_id=5

(taca)