freqsweep: fixing additional classifiers
freqsweep: fixing additional classifiers

Properly handle the case where additional classifiers are not specified.

jimboatarm/workload-automation,bjackman/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,bjackman/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation