Remove some unused color-theme overrides

After #7318 $link-color is used by default, no need to override anymore.

closes #7325

Changelog.md

@@ -3,6 +3,7 @@
 ## Refactor
 * Unify link colors [#7318](https://github.com/diaspora/diaspora/pull/7318)
 * Increase time to wait before showing the hovercard [#7319](https://github.com/diaspora/diaspora/pull/7319)
+* Remove some unused color-theme overrides [#7325](https://github.com/diaspora/diaspora/pull/7325)
 
 ## Bug fixes
 * Fix path to `bundle` in `script/server` [#7281](https://github.com/diaspora/diaspora/pull/7281)

app/assets/stylesheets/color_themes/_color_theme_override.scss

 /* Raw CSS */
 body {
-  a,
-  a.tag,
-  .btn-link,
-  #main_stream .stream-element > .media a.author-name,
-  #hovercard h4 a,
-  .stream-element .from a.self {
-    color: $link-color;
-
-    &:hover, &:focus {
-      color: darken($link-color, 10%);
-    }
-  }
-
   #publisher_textarea_wrapper > #button_container > span.markdownIndications > a {
     color: fade-out($link-color, 0.4);
   }