XWIKI-1342: Colibri theme - Mapping .vertical-menu

- Removed duplicates after https://github.com/evalica/bootswatch/commit/dee01dc6adb90c80160ef3feefe90ba36c4816c4 and https://github.com/evalica/bootswatch/commit/b9c1e6d3e520dbd31296d3fdd7beaa60c11395c9