If a distribution pipeline fails, the parent trigger job will be updated,
but the pipeline will not continue. It's a gitlab upstream issue, but
until it is fixed, add a workaround for it:
- we add a new stage right after the children pipelines which will be
  always run
- the jobs reflects the status of the total children pipelines
- when the downstream piplines are fixed, we can manually retrigger this
  job, and continue the pipeline

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>