Use principals in acts_as_watchable (#4511).

Patch by Marius BALTEANU.


git-svn-id: http://svn.redmine.org/redmine/trunk@19725 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/plugins/acts_as_watchable/lib/acts_as_watchable.rb

@@ -31,7 +31,7 @@ module Redmine
 
         # Returns an array of users that are proposed as watchers
         def addable_watcher_users
-          users = (self.project.users.sort + self.project.principals.merge(Group.givable).sort) - self.watcher_users
+          users = self.project.principals.where(:users => {:type => ['User', 'Group']}).sort - self.watcher_users
           if respond_to?(:visible?)
             users.reject! {|user| user.is_a?(User) && !visible?(user)}
           end