- Patch #201122 by c960657, Moshe Weitzman: never write anonymous sessions,...

- Patch #201122 by c960657, Moshe Weitzman: never write anonymous sessions, unless something has been written to . This is an important performance improvements -- as long as you use modules that use  carefully. It might be good to report some analytics about this in the performance settings page so administrators can see if there is a 'broken' module.