Revert r6104 "Merged r6098 from trunk."

I messed things up with a cherry-pick on master, I'll re-apply it after.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/1.2-stable@6105 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/setting.rb

@@ -75,7 +75,7 @@ class Setting < ActiveRecord::Base
                   TIS-620)
 
   cattr_accessor :available_settings
-  @@available_settings = YAML::load(File.open("#{Rails.root}/config/settings.yml"))
+  @@available_settings = YAML::load(File.open("#{RAILS_ROOT}/config/settings.yml"))
   Redmine::Plugin.all.each do |plugin|
     next unless plugin.settings
     @@available_settings["plugin_#{plugin.id}"] = {'default' => plugin.settings[:default], 'serialized' => true}