Filling out initial rubocop support for metadata.rb and the Gemfile.

https://blueprints.launchpad.net/openstack-chef/+spec/lint-and-unit-testing-for-havana
Removing tailor, cleaning up metadata and Gemfile, added TESTING.md and fixed a
broken test.

Addresses: blueprint rubocop-for-metering
Change-Id: I5a712c18033b6586548903dea93c8421050d971e
Merge "Filling out initial rubocop support for metadata.rb and the Gemfile."