Blueprint package set is now depsolved together with the OS package set
in a chain. The result is stored in the package specs sets under the OS
package set name.
In reality, the code was able to handle a `nil` package specs to be
passed to pipelines, however some parts were looking for the kernel
version in the blueprint package specs, which would be a bug.
Regenerated affected image test cases.
Add the `gce` image type intended for Google Compute Engine. The image
is BYOS - bring your own subscription and requires registering in order
to access Red Hat content.
Signed-off-by: Tomas Hozza <thozza@redhat.com>
