Merge "libsnapshot: cancel ok if unverified and old slot"

    UpdateState state = ReadUpdateState(file.get());

    if (state == UpdateState::None) return true;

    if (state != UpdateState::Initiated) {

        LOG(ERROR) << "Cannot cancel update after it has completed or started merging";

        return false;

    if (state == UpdateState::Initiated) {

        LOG(INFO) << "Update has been initiated, now canceling";

        return RemoveAllUpdateState(file.get());

    }

    if (state == UpdateState::Unverified) {

        // We completed an update, but it can still be canceled if we haven't booted into it.

        auto boot_file = GetSnapshotBootIndicatorPath();

        std::string contents;

        if (!android::base::ReadFileToString(boot_file, &contents)) {

            PLOG(WARNING) << "Cannot read " << boot_file << ", proceed to canceling the update:";

            return RemoveAllUpdateState(file.get());

        }

        if (device_->GetSlotSuffix() == contents) {

            LOG(INFO) << "Canceling a previously completed update";

            return RemoveAllUpdateState(file.get());

        }

    }

    LOG(ERROR) << "Cannot cancel update after it has completed or started merging";

    return false;

}

bool SnapshotManager::RemoveAllUpdateState(LockedFile* lock) {

    if (!RemoveAllSnapshots(lock)) {