Use ctime instead of creationTime in backup objects

src/account/NetworkPage.vue

@@ -203,7 +203,7 @@
                     let lastBackup = this.backups[0];
                     return '<hr/>' + this.messages.label_latest_backup
                            + " " + lastBackup.label + " <i>" + lastBackup.status + "</i> "
-                           + this.messages.date_format_app_data_epoch_time.parseDateMessage(lastBackup.creationTime,
+                           + this.messages.date_format_app_data_epoch_time.parseDateMessage(lastBackup.ctime,
                                                                                             this.messages);
                 }
             },