Don't fail if new filter is added.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11401 e93f8b46-1217-0410-a6f0-8f06a7374b81
Adds closed_on column that stores the time of the last closing (#824).

The value is preserved when reopening the issue.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11402 e93f8b46-1217-0410-a6f0-8f06a7374b81
Makes closed_on available as column and filter on the issue list (#824).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11403 e93f8b46-1217-0410-a6f0-8f06a7374b81
Adds field_closed_on to locales (#824).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@11404 e93f8b46-1217-0410-a6f0-8f06a7374b81