FIX-change .LanguagePrefix to .Site.LanguagePrefix

This change is made to ensure compatibility with future version of hugo

layouts/partials/menu.html

@@ -2,7 +2,7 @@
   <nav>
     <ul class="row menu">
       <li class="col-xs-12 col-md-2">
-        <a href="{{ if .LanguagePrefix }}{{ .LanguagePrefix }}{{ else }}/{{ end }}">
+        <a href="{{ if .Site.LanguagePrefix }}{{ .Site.LanguagePrefix }}{{ else }}/{{ end }}">
           <img class="img-responsive" src="/img/icon.png" width="128" height="128" alt="Redox Logo"/>
         </a>
       </li>