Fixes #7233 - Drop Ruby 1.8.7 and revert Ruby 1.8.7 specifics

- [x] rake test passed
- [x] rails server loaded and function correctly
- [x] Ubuntu 12.04 packaging blocker issue 
- [x] drop 1.8.7 tests on Jenkins
You need to update lib/foreman.rb to use SecureRandom if you're dropping the dep entirely: http://projects.theforeman.org/issues/8461

It's installed by luck right now, as google-api-client depends on it.