Fix test on wrong file
Use die helper
Add helpers to read/write json

This is taken from install-chef-suse.sh
Use new helpers to read/write json
Check that /etc/crowbar/provisioner.json contains what we need

We will update the provisioner proposal with the Cloud 3 URLs for repos
if it had Cloud 2.0 URLs. To do that, we first need to check that
/etc/crowbar/provisioner.json has the URLs we need (if the provisioner
proposal is using any URL).

We also check that addition URL in /etc/crowbar/provisioner.json are
really wanted because they will be added to the provisioner proposal.
Update provisioner proposal with repos in /etc/crowbar/provisioner.json

If there is information about repositories in
/etc/crowbar/provisioner.json (and that would include manual Cloud 3
repos), then update the provisioner proposal accordingly. We also drop
any Cloud 2.0 information we might have.

Note that we do not commit the provisioner proposal; this would have to
be done manually.
Fix wrong variable name
Fix ask_yes_no_default_no to work when using logging