Comment 0 for bug 1724623

add_cloud_info() in data/general-hooks/ubuntu.py needs an overhaul.

Issues:
 - Using the presence of cloud-init to flag an image as a cloud image is incorrect now that ubuntu-server includes cloud-init (and ubuntu-core images)
 - Using the presence of EC2 metadata source is incorrect as many non-EC2 clouds provide EC2 metadata. Thus we have bugs like bug #1722946 that are tagged as an 'ec2-images' bug which are clearly on openstack
 - Marking all bugs that have cloud-init but no EC2 metadata source as an 'uec-images' bug uses a name that no longer has meaning.

Solution:
 - If cloud-init is present, check for /etc/cloud/build.info to indicate an Ubuntu cloud images, tag as 'cloud-images'. Pull the build_name and serial from that file into the bug comments.
 - If cloud-init is present, check for the presence of /run/cloud-init/cloud.cfg. Parse this yaml to determine the datasource type. Add the datasource used to the bug comment.

We should also ask cloud-init development to surface more information from ds-identify to help ID the cloud so that we can better tag/annotate the bug. There may also be some info we can get to indicate the image ID on more clouds than just AWS. At a minimum I would like to see dsidentify make the EC2 platform it found available for consumers in cloud.cfg. This would allow us to identify AWS EC2 from look-alike datasources so that we can tag a bug as ec2-images for bug really on AWS and add EC2 specific fields to the description/attachments.