MAGETWO-48070: Remove or comment next files: web/css/course: dropdown.less and rating.less

- Removed dropdown.less and rating.less

Author: Oleksandr Dubovyk

app/design/frontend/Magento/blank/web/css/source/_dropdowns.less

@@ -16,9 +16,7 @@
 @import '_icons.less';
 @import '_buttons.less';
 @import '_sections.less';
-@import '_dropdowns.less';
 @import '_pages.less'; // Theme pager
-@import '_rating.less';
 @import '_actions-toolbar.less';
 @import '_breadcrumbs.less';
 @import '_popups.less';