Remote image server generator of server code skips metadata of existing images

If you share a file_ubuntu between two different channels and they have multiple devices, that means the first to be processed will retrieve the image, load its metadata and fill the environment with it just fine. However, the next ones will skip this metadata parsing as the remote image server generator simply returns as soon as it sees an existing image file, without loading its json again and thus not filling the environment with the needed information. I've linked a branch that address that.