Search.Filter.HTML: Fix title always being set to "".

Fixes #10020.

lib/modules/Search.pmod/Filter.pmod/HTML.pmod

@@ -368,15 +368,15 @@ static string clean(string data) {
 				 }
 			       });
 
-  res->fields->title="";
-  res->fields->description="";
-  res->fields->keywords="";
-
   parser->finish(data);
 
   res->links = lf->read();
   res->fields->body=databuf->get();
   res->fix_relative_links(uri);
 
+  res->fields->title = res->fields->title || "";
+  res->fields->description = res->fields->description || "";
+  res->fields->keywords = res->fields->keywords || "";
+
   return res;
 }