Clear @assignable_users on reload.

git-svn-id: http://svn.redmine.org/redmine/trunk@13510 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/project.rb

@@ -311,6 +311,7 @@ class Project < ActiveRecord::Base
     @start_date = nil
     @due_date = nil
     @override_members = nil
+    @assignable_users = nil
     base_reload(*args)
   end