Revert "Changed the date format so that start date and end date of the sprint don't"

This reverts commit 22875a468d.

app/helpers/backlogs_helper.rb

@@ -2,22 +2,22 @@ module BacklogsHelper
 
   def backlog_date(backlog, field_name)
     d = backlog.send(field_name)
-    d.nil? ? "(not set)" : d.strftime("%m-%d-%y")
+    d.nil? ? "(not set)" : d.strftime("%Y-%m-%d")
   end
-
+  
   def mark_closed_if_so(item_or_task)
     return if item_or_task.nil?
     item_or_task.issue.status.is_closed? ? "closed" : ""
   end
-
+    
   def link_to_main_backlog
     link_to "All Backlog Items", :controller => 'items', :project_id => @project.id
   end
-
+  
   def link_to_backlog(backlog)
     link_to backlog.version.name, backlog_url(backlog)
   end
-
+  
   def say_version(issue)
     issue.fixed_version.nil? ? "-" : issue.fixed_version.name
   end