Allow placing blocks in spawn if ops.txt is empty. Fixes BUKKIT-3004

By: Travis Watkins <amaranth@ubuntu.com>

paper-server/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java

@@ -68,6 +68,7 @@ public class CraftEventFactory {
 
         if (world.getHandle().dimension != 0) return true;
         if (spawnSize <= 0) return true;
+        if (((CraftServer) Bukkit.getServer()).getHandle().getOPs().isEmpty()) return true;
         if (player.isOp()) return true;
 
         ChunkCoordinates chunkcoordinates = worldServer.getSpawn();