Revert "Fail on flush if no sensors are found" am: fb64fca3

    const int halVersion = dev.getHalDeviceVersion();

    status_t err(NO_ERROR);

    Mutex::Autolock _l(mLock);

    size_t numSensors = 0;

    // Loop through all sensors for this connection and call flush on each of them.

    for (int handle : connection->getActiveSensorHandles()) {

        sp<SensorInterface> sensor = getSensorInterfaceFromHandle(handle);

        if (sensor == nullptr) {

            continue;

        }

        numSensors++;

        if (sensor->getSensor().getReportingMode() == AREPORTING_MODE_ONE_SHOT) {

            ALOGE("flush called on a one-shot sensor");

            err = INVALID_OPERATION;

            continue;

        }

        if (halVersion <= SENSORS_DEVICE_API_VERSION_1_0 || isVirtualSensor(handle)) {

            // For older devices just increment pending flush count which will send a trivial

            // flush complete event.

            err = (err_flush != NO_ERROR) ? err_flush : err;

        }

    }

    return (numSensors == 0) ? INVALID_OPERATION : err;

    return err;

}

bool SensorService::canAccessSensor(const Sensor& sensor, const char* operation,