Fix wiki new pages

templates/wiki.html

@@ -1,8 +1,10 @@
 {% extends 'base.html' %}
 
 {% block prehead %}
+    {% if wiki_page %}
         <meta name="author" content="{{ wiki_log.editor.username }}">
         <meta name="description" content="{{ wiki_page.content[:97] }}...">
+    {% endif %}
 {% endblock %}
 
 {% block pagetitle %}