Consider the site.disqus variable to decide whether import Disqus

Author: ngzhio

_layouts/post.html

@@ -80,7 +80,7 @@ <h1 class="post-title p-name" itemprop="name headline">{{ page.title | escape }}
     </nav>
   </footer>
 
-  {% if page.comments != false and jekyll.environment == "production" %}
+  {% if page.comments != false and jekyll.environment == "production" and site.disqus %}
     {% include disqus.html %}
   {% endif %}