Delete any deleteable images

def delete_deps(self, conf, images):
        """Delete any deleteable images"""
        for dependency_name, _ in conf.dependency_images():
            image = images[dependency_name]
            if image.deleteable_image:
                log.info("Removing un-needed image {0}".format(image.image_name))
                conf.harpoon.docker_api.remove_image(image.image_name)