Check that old pipelines have at least one job

At the moment, when checking for old pipelines, only the pipeline variables are taken into account. For broken pipelines with no jobs, this works as those have no variables. This is not the case for parent-child pipelines. Protect against broken pipelines getting proper variable support by also checking that old pipelines have any jobs at all.

Signed-off-by: Michael Hofmann mhofmann@redhat.com