Header top link if rule needs a better condition

Problem/Motivation

The code in bs_bootstrap/sass/layout/partials/_header.scss

    // General link rules.
    @if $header-top-link-color != $header-link-color {
      a:not([class]), a.ext {
        @include style-link($header-top-link-color, $header-top-link-hover-color);
      }
      ...

needs a better if check like

@if $header-top-link-color != $header-link-color or $header-top-link-hover-color != $header-link-hover-color