Item2565: Log when user changes email address

For audit trail and spam fighting we need to be able to see in the logs when a user changes email address

Often a spammer will register with a valid email address. Then when registration is confirmed he changes it to garbage or john@smith.com

Having a log entry that shows what the email was changes from and to gives the admin an extra tool in the toolbox to fight spammers and vandals.

-- KennethLavrsen - 03 Jan 2010