Delete push-jobs if old runit is configured

[afiune]

Description

[Describe what this change achieves]

Issues Resolved

[List any existing issues this PR resolves]

Check List

• [ ] All tests pass. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/TESTING.MD
• [ ] New functionality includes testing.
• [ ] New functionality has been documented in the README if applicable
• [ ] The CLA has been signed. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[thommay]

I think the sense of the change is correct, but it should also handle upstart and not just systemd, as per https://github.com/chef-cookbooks/push-jobs/issues/91

[afiune]

Great comments, working on them. 👍

[afiune]

@thommay @tas50 ready whenever you are!! 😸

[thommay]

LGTM once travis is happy.