Move to new Fstab class

using base::Trim;

using base::WriteStringToFd;

using base::WriteStringToFile;

using fs_mgr::Fstab;

using fs_mgr::ReadDefaultFstab;

std::string getGarbageCollectPath() {

    std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(),

                                                               fs_mgr_free_fstab);

    struct fstab_rec* rec = NULL;

    Fstab fstab;

    ReadDefaultFstab(&fstab);

    for (int i = 0; i < fstab->num_entries; i++) {

        if (fs_mgr_has_sysfs_path(&fstab->recs[i])) {

            rec = &fstab->recs[i];

            break;

        }

    for (const auto& entry : fstab) {

        if (!entry.sysfs_path.empty()) {

            return entry.sysfs_path + "/manual_gc";

        }

    if (!rec) {

        return "";

    }

    std::string path;

    path.append(rec->sysfs_path);

    path = path + "/manual_gc";

    return path;

    return "";

}

Return<void> Storage::garbageCollect(uint64_t timeoutSeconds,