message: don't close standard file descriptors (<=2)
diff: @@ -506,6 +506,7 @@ static void* vcpu_loop(struct kvm_run *run)
  unsigned data = *((unsigned*)((size_t)run+run->io.data_offset));
  uhyve_close_t* uhyve_close = (uhyve_close_t*) (guest_mem+data);
  + if (uhyve_close->ret > 2)
  uhyve_close->ret = close(uhyve_close->fd);
  break;
  }
  