[Web] fixed logo image informations

Signed-off-by: Kristian Feldsam <feldsam@gmail.com>

data/web/templates/admin/tab-config-customize.twig

@@ -12,7 +12,7 @@
       </form>
       {% if logo %}
         <div class="row">
-          <div class="col-sm-3">
+          <div class="col-sm-4">
             <div class="thumbnail">
               <img class="img-thumbnail" src="{{ logo }}" alt="mailcow logo">
               <div class="caption">