Core/Spells: move Cannibalize and Carrion Feeder cast checks to SpellScripts.

sql/updates/world/2011_08_19_03_world_spell_script_names.sql

@@ -0,0 +1,4 @@
+DELETE FROM `spell_script_names` WHERE `spell_id`=20577;
+INSERT INTO `spell_script_names` (`spell_id`,`ScriptName`)
+VALUES
+(20577,'spell_gen_cannibalize');