upgrade Rails to 3.2.12

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11353 e93f8b46-1217-0410-a6f0-8f06a7374b81
remove trailing white-spaces from app/models/custom_field.rb

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11354 e93f8b46-1217-0410-a6f0-8f06a7374b81