Merged r5880 from trunk.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/branches/1.2-stable@5945 e93f8b46-1217-0410-a6f0-8f06a7374b81

vendor/plugins/acts_as_watchable/lib/acts_as_watchable.rb

@@ -13,7 +13,7 @@ module Redmine
           
           class_eval do
             has_many :watchers, :as => :watchable, :dependent => :delete_all
-            has_many :watcher_users, :through => :watchers, :source => :user
+            has_many :watcher_users, :through => :watchers, :source => :user, :validate => false
             
             named_scope :watched_by, lambda { |user_id|
               { :include => :watchers,