Make the 'duplicates of' relation asymmetric:

* closing a issue will close its duplicates
* closing a duplicate won't close the main issue

git-svn-id: http://redmine.rubyforge.org/svn/trunk@1488 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/issue_relation.rb

@@ -25,7 +25,7 @@ class IssueRelation < ActiveRecord::Base
   TYPE_PRECEDES     = "precedes"
   
   TYPES = { TYPE_RELATES =>     { :name => :label_relates_to, :sym_name => :label_relates_to, :order => 1 },
-            TYPE_DUPLICATES =>  { :name => :label_duplicates, :sym_name => :label_duplicates, :order => 2 },
+            TYPE_DUPLICATES =>  { :name => :label_duplicates, :sym_name => :label_duplicated_by, :order => 2 },
             TYPE_BLOCKS =>      { :name => :label_blocks, :sym_name => :label_blocked_by, :order => 3 },
             TYPE_PRECEDES =>    { :name => :label_precedes, :sym_name => :label_follows, :order => 4 },
           }.freeze