Merge pull request #20 from norv/master

Small miss in upgrade scripts

other/upgrade_2-1_mysql.sql

@@ -141,7 +141,7 @@ ALTER TABLE {$db_prefix}log_errors
 CHANGE `session` char(64) NOT NULL default '                                                                ';
 
 ALTER TABLE {$db_prefix}sessions
-CHANGE `session_id` char(64) NOT NULL default '';
+CHANGE `session_id` char(64) NOT NULL;
 ---#
 
 /******************************************************************************/

other/upgrade_2-1_postgresql.sql

@@ -145,7 +145,7 @@ ALTER TABLE {$db_prefix}log_errors
 CHANGE `session` char(64) NOT NULL default '                                                                ';
 
 ALTER TABLE {$db_prefix}sessions
-CHANGE `session_id` char(64) NOT NULL default '';
+CHANGE `session_id` char(64) NOT NULL;
 ---#
 
 /******************************************************************************/

other/upgrade_2-1_sqlite.sql

@@ -141,7 +141,7 @@ ALTER TABLE {$db_prefix}log_errors
 CHANGE `session` char(64) NOT NULL default '                                                                ';
 
 ALTER TABLE {$db_prefix}sessions
-CHANGE `session_id` char(64) NOT NULL default '';
+CHANGE `session_id` char(64) NOT NULL;
 ---#
 
 /******************************************************************************/