added "upstart" init_style

[eugene-dm]

upstart is available for CentOS also

[adamkrone]

@eugene-dm sorry, I missed the notification when you opened this PR.

I'd like to merge this, but before I do can you update a few things?

• keep the version in metadata.rb the same (after I merge this I will be releasing this, and some other changes, as v0.9)
• fix the case indentation in service.rb (case and when/else should be at same level). This follows the ruby styleguide and is enforced with rubocop.
• fix the indentation of the arguments starting on lines 90, 109, and 120 of service.rb. Indentation should be 2 spaces. Same as above, this is laid out in the ruby styleguide.

The last two items should fix all the travis-ci errors. You can run bundle exec rake locally to validate rubocop/tests pass before pushing up your fixes.

[eugene-dm]

@adamkrone, I've updated styles, so checks are passed and you can merge this pull request

[adamkrone]

@eugene-dm awesome, thanks a lot!