Custom images

This command failed for me.

```
tar  --numeric-owner -czf /vz/template/cache/new-custom-image-temp.tar.gz
tar: Cowardly refusing to create an empty archive
Try `tar --help' or `tar --usage' for more information.
```

Using this command instead worked. (Just added the current directory as an argument)

```
tar  --numeric-owner -czf /vz/template/cache/new-custom-image-temp.tar.gz .
```