Fixed: queries error messages about custom fields output a 'translation missing' error (#8554).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@6126 e93f8b46-1217-0410-a6f0-8f06a7374b81
use same human_attribute_name logic with SCM models at group model

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8237 e93f8b46-1217-0410-a6f0-8f06a7374b81
human_attribute_name accepts optional argument.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8286 e93f8b46-1217-0410-a6f0-8f06a7374b81
Rails3: use .to_s for overriding human_attribute_name parameter at group model

On Rails 3.0.11, parameter is symbol not string in activerecord validation.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8969 e93f8b46-1217-0410-a6f0-8f06a7374b81