The label `__meta_digitalocean_image` expose the `slug` of the image and
the `slug` is only present in the public images.
To refer a user-generated image (`snapshot` or `custom`) we can use
the image's display name.
See: https://developers.digitalocean.com/documentation/v2/#images
Signed-off-by: Matteo Valentini <matteo.valentini@nethesis.it>
This also fixes a bug in query_log_file, which now is relative to the config file like all other paths.
Signed-off-by: Andy Bursavich <abursavich@gmail.com>