Add ruby-1.9.3-p374

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-list/49138 (release mail in Japanese)
http://svn.ruby-lang.org/repos/ruby/tags/v1_9_3_374/ChangeLog# Requesting a pull to sstephenson:master from sorah:193p374

http://www.ruby-lang.org/en/news/2013/01/17/ruby-1-9-3-p374-is-released/