Avoid redownloding .deb file

The task `Download Elasticsearch deb` is now always downloading the `.deb` file.

For [get_url](https://github.com/ansible/ansible/blob/devel/library/network/get_url#L277-L279) to skip downloading the remote file, these conditions should be met:

* `dest` is not a directory
* `force` is `no`

```pyhon
    if not dest_is_dir and os.path.exists(dest):
        if not force:
            module.exit_json(msg="file already exists", dest=dest, url=url, changed=False)
```

So specifying full path to the `dest` attr should fix this.