Fix NPE from location incorrectly being implemented in Explosion.

src/main/java/net/minecraft/server/Explosion.java

@@ -29,10 +29,6 @@ public class Explosion {
     public float f;
     public Set g;
 
-    // CraftBukkit
-    // Retain where the explosion happened because the Entity no longer exists after explosion.
-    private Location location;
-
     public Explosion(World world, Entity entity, double d1, double d2, double d3, float f1) {
         a = false;
         h = new Random();
@@ -44,7 +40,6 @@ public class Explosion {
         c = d2;
         d = d3;
 
-        location = entity.getBukkitEntity().getLocation();
     }
 
     public void a() {
@@ -189,6 +184,7 @@ public class Explosion {
         Server server = ((WorldServer) i).getServer();
         CraftWorld world = ((WorldServer) i).getWorld();
         org.bukkit.entity.Entity splode = (e == null) ? null : e.getBukkitEntity();
+        Location location = new Location(world, b, c, d);
 
         List<org.bukkit.block.Block> blocklist = new ArrayList<org.bukkit.block.Block>();
         for (int j = arraylist.size() - 1; j >= 0; j--) {