SPIGOT-4101: Turtle lightning strike causing crash

nms-patches/EntityTurtle.patch

@@ -0,0 +1,12 @@
+--- a/net/minecraft/server/EntityTurtle.java
++++ b/net/minecraft/server/EntityTurtle.java
+@@ -260,7 +260,9 @@
+     }
+ 
+     public void onLightningStrike(EntityLightning entitylightning) {
++        org.bukkit.craftbukkit.event.CraftEventFactory.entityDamage = entitylightning; // CraftBukkit
+         this.damageEntity(DamageSource.LIGHTNING, Float.MAX_VALUE);
++        org.bukkit.craftbukkit.event.CraftEventFactory.entityDamage = null; // CraftBukkit
+     }
+ 
+     public void die(DamageSource damagesource) {