DB/Creature: Add a new extra_flag CREATURE_FLAG_EXTRA_NO_PLAYER_DAMAGE_REQ (0x00200000) that awards players credit for killing the creature even if less than 50% of damage was dealt by players.

This can be used to fix quests such as "Heated Battle" or "If Valgarde Falls..." that are currently very hard to complete at the appropriate level due to "friendly" NPCs killing off the required targets too quickly for players to get 50% of damage in.

sql/updates/world/2016_01_13_playerdamagereq.sql

@@ -0,0 +1,5 @@
+-- Transition some creatures to use new CREATURE_FLAGS_EXTRA_NO_PLAYER_DAMAGE_REQ
+-- 27685/27686/27531: Target creatures for Quest 12416 ("Heated Battle")
+-- 24051/24063: Target creatures for Quest 11243 ("If Valgarde Falls...")
+-- 28034/28035/28036: Targets for Quest 12508 ("Mopping Up")
+UPDATE `creature_template` SET `flags_extra`=(`flags_extra`|2097152) WHERE `entry` IN (27685,27686,27531,24051,24063,28034,28035,28036);