Remove Linter superclass from LinterRegistry
Remove Linter superclass from LinterRegistry

The superclass `Linter` was incorrectly being returned in the list of
registered linters. Remove the inclusion of the `LinterRegistry` module
to remove it.

This didn't previously have any negative effect because the `Linter`
class `run` method is effectively a no-op.

Change-Id: I1199f0b35ff16f693d3d17e99288cd93add4200b
Reviewed-on: https://gerrit.causes.com/27622
Tested-by: jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@causes.com>
Reviewed-by: Kim Douglas Clarence Mason <b21f0a9a26d2288a382e1db897c9c0db98688f4c@causes.com>

artemartemov/scss-lint-hdm