Update breadcrumb.html

fix breadcrumb generation conditional logic

Author: michaelbabyn

_includes/breadcrumb.html

@@ -33,7 +33,7 @@
             </li>
             {% endif %}
 
-            {% if page.display_as != blank %}
+            {% if page.display_as %}
             {% assign display_as = site.data.display_as[page.display_as] %}
 	    {% assign langue = page.language %}
 	    {% if page.permalink contains 'javascript' %}