DB: Remove skinloot from Critters

By @tkrokli
Closes #15871

sql/updates/world/2015_11_23_01_world_335.sql

@@ -0,0 +1,3 @@
+UPDATE `creature_template` SET `skinloot` = 0 WHERE `entry` IN (721,883,890,1933,2098,2442,2620,4166,5951,10780,12296,12297,12298,12299,17467);
+-- Remove unreferenced skinning_loot_template entries because of this update:
+DELETE FROM `skinning_loot_template` WHERE `Entry` IN (1933,12299,100000);