Minor: changed order of execution to avoid warning

main/calendar/download.php

@@ -63,11 +63,11 @@ $sql='SELECT filename FROM '.$tbl_agenda_attachment.'
   	  WHERE path LIKE BINARY "'.Database::escape_string($doc_url).'"';
 
 $result = Database::query($sql);
-$row    = Database::fetch_array($result);
 if (Database::num_rows($result) > 0) {
+    $row    = Database::fetch_array($result);
     $title = str_replace(' ','_', $row['filename']);
     if (Security::check_abs_path($full_file_name, api_get_path(SYS_COURSE_PATH).api_get_course_path().'/upload/calendar/')) {
         DocumentManager::file_send_for_download($full_file_name,TRUE, $title);
     }
 }
-exit;
+exit;