Allow null value for dkim fields in mail_user table.

Till Brehm

2014-03-28 8edc7f1985d803e684eea22a8adb042a66b777e3

1
ALTER TABLE  `sys_session` CHANGE  `session_id`  `session_id` VARCHAR( 64 ) CHARACTER SET latin1 COLLATE latin1_swedish_ci NOT NULL;