incorrect string to bool conversions when parsing command line arguments

[abolshov]

When appending command line arguments for further ps_call via analysisCacheProducer_cmd.extend(["--compute_unc_variations", "True"]), incorrect string to bool conversion occurs: no matter what the value of the string command line argument is, after adding it as parser.add_argument("--compute_unc_variations", type=bool, default=False), resulting argument is converted to bool as string, meaning that if the string is not empty, args.compute_unc_variations=True (even if --compute_unc_variations was passed as False). To reproduce one can run e.g. AnalysisCacheTask with --compute_unc_variations False and print args.compute_unc_variations from AnalysisCacheProducer. I suspect that might be an issue in more places.