Serverspec update, slave fixes/simplifications

- don't bomb out if master isn't found, fixes
- clean up conditionals to make a much cleaner recipe
- syntax fix for serverspec v2.0
- more lint for FC and Rubocop
- changing logging interface used in _find_master recipe
- removed build-essentials from compile time due to build errors
- added read of pub keys, rubocop fixes
- fix for runit and chef-sugar