tauRecTools: only store the RNN ID variable calculators actually used
Hello,
This MR is optimising a bit the RNN tau ID code, which uses maps to hold scalar-, track- and cluster-based variable calculators in memory. We use 5 RNNs in tau offline recontruction: 1p/2p/3p tau ID, and 1p/3p tau-electron veto. Each use a different set of input variables. However currently, we store all possible calculators in these maps. With this MR, we will only store the variable calculators atually used by a given RNN.
Minor other change: in one track variable calculator, I dropped a protection against missing ID tracks, as it's no longer necessary.
Cheers, Bertrand