loop over nBin not starting from 1 like TH1D

[nadrino]

After a successful fit, GUNDAM would complain while writing a breakdown of llh:

2024.11.29 16:59:35  INFO RootMinimizer: Minimization ended after 46225 calls.
2024.11.29 16:59:35  WARN RootMinimizer: Status code: status = 0    : OK
2024.11.29 16:59:35  WARN RootMinimizer: Covariance matrix status code: status = 3    : accurate
2024.11.29 16:59:35  WARN RootMinimizer: Updating propagator cache to the best fit point...
2024.11.29 16:59:35  INFO RootMinimizer: Writing Minuit2/Migrad best fit parameters...
2024.11.29 16:59:35 ALERT RootMinimizer: Skipping saveGradientSteps as light output mode is fired.
2024.11.29 16:59:35  INFO RootMinimizer: Minimization has converged!
2024.11.29 16:59:35  INFO RootMinimizer: Writing convergence stats...
2024.11.29 16:59:35 ERROR BarlowBeestonBanff2022: BBNoUpdateWeights mcuncert is not valid -nan
2024.11.29 16:59:35 ERROR BarlowBeestonBanff2022: nomMC bin 154 error is -nan(virtual double JointProbability::BarlowBeestonBanff2022::eval(const SamplePair&, int) const): The mc uncertainty is not a usable number