logger function like dinfo turn off xtrace unless environment variable debug set

logger functions like dinfo will disable xtrace unexpectedly,
```bash
ddebug()
{
	set +x
	dlog 4 "$@"
	if [ -n "$debug" ]; then
		set -x
	fi
}

dinfo()
{
	set +x
	dlog 3 "$@"
	if [ -n "$debug" ]; then
		set -x
	fi
}

```
As a result, `bash -x kdumpctl` or `shellspec -x` may show incomplete xtrace. I'm not sure if we should re-enable xtrace automatically if we detect `x` in `"$-"`