Open Stack

How many times did we have broken Gem dependencies, for different reasons?
A lot, maybe too much. It's time to find a way to centralize Gems
dependencies, like other OpenStack project already do with
openstack/requirements and Python dependencies.

So I submitted this patch: https://review.openstack.org/#/c/298465/
(that is tested and work, look comments), which aims to use
puppet-openstack_spec_helper.gemspec as a single place to manage our
dependencies.
Next time we need to change the version of a Gem for our CI jobs, we
will just have to patch this file. That's it.

And a serie of patches in our modules:
https://review.openstack.org/#/q/topic:common-gemfile to make sure we
don't install the dependencies from Gemfiles.

I also propose we backport this thing, at least in stable/mitaka. It
will make our life much easier next time a Gem is broken and help to
maintain stable branches CI in a good shape.
Please give any feedback and use Gerrit to review the work in progress,

Thanks,
-- 
Emilien Macchi