proper keyword for i18n support

Author: serghey-rodin

web/templates/admin/list_backup.html

@@ -172,7 +172,7 @@
                     <td>
                         <?php
                             if ( $i == 1) {
-                                echo __('one archive');
+                                echo __('1 archive');
                             } else {
                                 echo __('%s archives',$i);
                             }