Teach scss-lint BorderZeroLinter about border-side

This linter originally only complained about `border: none;`. Now it
complains also about `border-top: none;` and its ilk.

Change-Id: I5969c0cf4d47aa3d229326225b8b2a1fa04a5eb1
Reviewed-on: https://gerrit.causes.com/22772
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Aiden Scandella <aiden@causes.com>