Add a auto-remove for the button if no link exsists

aleksis/core/templates/core/data_check/list.html

@@ -60,9 +60,11 @@
                 <td>{{ result.related_object }}</td>
                 <td>{{ result.related_check.problem_name }}</td>
                 <td>
+		  {% if result.related_object.get_absolute_url %}
                   <a class="btn-flat waves-effect waves-light" href="{{ result.related_object.get_absolute_url|remove_prefix:"/django/" }}" target="_blank">
                     {% trans "Show object" %}
                   </a>
+		  {% endif %}
                 </td>
                 <td>
                   {% for option_name, option in result.related_check.solve_options.items %}