Define Principal#name so all subclasses will have some sort of name when printed.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4076 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/principal.rb

@@ -34,6 +34,10 @@ class Principal < ActiveRecord::Base
   
   before_create :set_default_empty_values
 
+  def name(formatter = nil)
+    to_s
+  end
+
   def <=>(principal)
     if self.class.name == principal.class.name
       self.to_s.downcase <=> principal.to_s.downcase