SPIGOT-1515: Use CUSTOM reason for GENERIC damage

src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -551,7 +551,7 @@ public class CraftEventFactory {
         } else if (source == DamageSource.FLY_INTO_WALL) {
             cause = DamageCause.FLY_INTO_WALL;
         } else if (source == DamageSource.GENERIC) {
-            return new EntityDamageEvent(entity.getBukkitEntity(), null, modifiers, modifierFunctions);
+            cause = DamageCause.CUSTOM;
         }
 
         if (cause != null) {
@@ -581,7 +581,7 @@ public class CraftEventFactory {
     private static final Function<? super Double, Double> ZERO = Functions.constant(-0.0);
 
     public static EntityDamageEvent handleLivingEntityDamageEvent(Entity damagee, DamageSource source, double rawDamage, double hardHatModifier, double blockingModifier, double armorModifier, double resistanceModifier, double magicModifier, double absorptionModifier, Function<Double, Double> hardHat, Function<Double, Double> blocking, Function<Double, Double> armor, Function<Double, Double> resistance, Function<Double, Double> magic, Function<Double, Double> absorption) {
-        Map<DamageModifier, Double> modifiers = new EnumMap<DamageModifier, Double>(DamageModifier.class);
+            Map<DamageModifier, Double> modifiers = new EnumMap<DamageModifier, Double>(DamageModifier.class);
         Map<DamageModifier, Function<? super Double, Double>> modifierFunctions = new EnumMap<DamageModifier, Function<? super Double, Double>>(DamageModifier.class);
         modifiers.put(DamageModifier.BASE, rawDamage);
         modifierFunctions.put(DamageModifier.BASE, ZERO);