erp5_discussion: Do not display a link to the author image when image is empty

bt5/erp5_discussion/SkinTemplateItem/portal_skins/erp5_discussion/DiscussionPost_getAuthorDict.xml

@@ -66,7 +66,7 @@ if author is not None:\n
   result[\'author_signature\'] = portal.ERP5Site_getUserPreferredForumSettingsDict(author.getReference())[\'preferred_forum_signature\']\n
   result[\'author_title\'] = author.getTitle()\n
   thumbnail = author.getDefaultImage()\n
-  if thumbnail is not None:\n
+  if thumbnail is not None and thumbnail.hasData():\n
     result[\'author_thumbnail_url\'] = thumbnail.absolute_url()\n
 \n
 return result\n

bt5/erp5_discussion/bt/revision

-137
+138
\ No newline at end of file