bug 1070: fix a pLoader bug on Piwigo side. Catch the bad communication:

don't try to find tags if tag_ids parameter is empty (but not null).

git-svn-id: http://piwigo.org/svn/branches/2.0@3659 68402e56-0260-453c-a942-63ccdbb3a9ee

include/ws_functions.inc.php

@@ -1214,7 +1214,7 @@ SELECT
   }
 
   // and now, let's create tag associations
-  if (isset($params['tag_ids']))
+  if (isset($params['tag_ids']) and !empty($params['tag_ids']))
   {
     set_tags(
       explode(',', $params['tag_ids']),