delete (failure) tasks when restart

[PPeanutButter]

when failure tasks been restarted manually, both will exist in Other Tasks(waitting, success or failure), it will be difficult to make sure whether failure tasks has been restarted especially task failed more than once

this can make sure deletes after new task been created

ARIA2.request("getOption", [gid], function(result) {
    var options = result.result;
    ARIA2.madd_task(uris, options);
    //delete old info(mostly failure), won`t delete file from disk actually.
    ARIA2.remove_result(gid);
});