Closed issue are not overdue, fixes r2140 (#2337).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2361 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/issue.rb

@@ -215,7 +215,7 @@ class Issue < ActiveRecord::Base
   
   # Returns true if the issue is overdue
   def overdue?
-    !due_date.nil? && (due_date < Date.today)
+    !due_date.nil? && (due_date < Date.today) && !status.is_closed?
   end
   
   # Users the issue can be assigned to