replace RAILS_ROOT to Rails.root at lib/redmine/version.rb.
replace RAILS_ROOT to Rails.root at lib/redmine/i18n.rb.
replace RAILS_ROOT to Rails.root in test/test_helper.rb.
back out r6078.
NoMethodError: undefined method `mkdir_p' for #<Pathname:0x7f56f9deb3c0>
replace RAILS_ROOT to Rails.root in test/fixtures/repositories.yml.
replace RAILS_ROOT to Rails.root in functional attachments controller test.
replace RAILS_ROOT to Rails.root in setting model.
replace RAILS_ROOT to Rails.root if functional application controller test.
replace RAILS_ROOT to Rails.root of attachments storage path.