Fix "DEPRECATION WARNING: Calling '<<' to an ActiveModel::Errors message array in order to add an error is deprecated." (#29914, #34985).

git-svn-id: http://svn.redmine.org/redmine/trunk@20898 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/sudo_mode.rb

@@ -20,7 +20,7 @@ module Redmine
 
       def check_password
         unless password.present? && User.current.check_password?(password)
-          errors[:password] << :invalid
+          errors.add(:password, :invalid)
         end
       end
     end