Remove explicit require of departed file.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4113 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

railties/bin/rails

 require File.dirname(__FILE__) + '/../lib/ruby_version_check'
 Signal.trap("INT") { puts; exit }
 
-require File.dirname(__FILE__) + '/../lib/rails_version'
+require File.dirname(__FILE__) + '/../lib/rails/version'
 abort "Rails #{Rails::VERSION::STRING}" if %w(--version -v).include? ARGV.first
 
 require File.dirname(__FILE__) + '/../lib/rails_generator'