attempt sha1(), password() and if mysql >= 4.0x, old_password() hashes. Switch the default user
hash from mysql's password() function to a sha1() hash. Update user::login() to flag logins
with password() and old_password() hashes. If the flag is set we call user::update_password()
to update the users password hash to one generated from the sha1 of the users password. Add a
unit test to test logging in and upgrading from the old hashes.
