Core/Achievements: pick more changes from 4.3.4/6.x branch, required after abee9046a6

sql/updates/world/2015_02_23_00_world.sql

@@ -0,0 +1,4 @@
+DELETE FROM `achievement_criteria_data` WHERE `criteria_id` IN (6847, 7849);
+INSERT INTO `achievement_criteria_data` (`criteria_id`, `type`, `value1`, `value2`, `ScriptName`) VALUES
+(6847, 12, 0, 0, ''),
+(7849, 12, 1, 0, '');