Use File.join to generate paths

[balasankarc]

Description

Using "#{foo}/#{bar}" for generating paths is little error prone (for example, if someone makes a mistake and sets foo = '/var/log/; bar = 'service', the path becomes foo//bar due to the trailing slash). Even though technically not an error, this may cause test failures where foo/bar is explicitly tested.

Using ::File.join even though a bit of extra work, is safer.

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
• [ ] All commits have been signed for the Developer Certificate of Origin. See https://github.com/chef-cookbooks/community_cookbook_documentation/blob/master/CONTRIBUTING.MD

[balasankarc]

@tas50 Could you take a look? From what I see, the CI failures are similar to what is seen in master, and are unrelated to this PR.

[tas50]

Looks good now. We should have done this a long time ago. Thanks for taking the time to clean it all up.