[2442] Always show a format icon for a resource

ckan/templates/package/read.html

@@ -41,7 +41,7 @@ <h3>Data and Resources</h3>
             <ul class="resource-list" py:if="c.pkg_dict.resources">
               <li class="resource-item" py:for="res in c.pkg_dict.resources" py:with="url=h.url_for(controller='package', action='resource_read', id=c.pkg_dict['name'], resource_id=res['id'])">
                 <a class="heading" href="${url}" title="${res.name or res.description}">
-                  ${h.resource_display_name(res)}<span py:if="res.format" class="format-label" property="dc:format" data-format="${res.format.lower()}">${res.format}</span>
+                  ${h.resource_display_name(res)}<span class="format-label" property="dc:format" data-format="${res.format.lower() or 'data'}">${res.format}</span>
                   <!--! TODO: Correctly pass localised views into this snippet -->
                   <py:if test="True" py:with="title=('%s views' % 10)">${h.snippet('snippets/popular.html', title=title)}</py:if>
                 </a>