SetBranchValue produces malformed Ntuples when not called before the first call to TTree::Fill() #327
Description
In OutNtupleProc, SetBranchValue is used to write the result of event fitters. This interacts badly when the fitter result is not present for all events -- either when a MC event does not trigger, or when a fitter fails to write out FOMs in some conditions. This is a general bug that #326 partially fixes. We may want to rethink our approach on writing fitter results. A similar approach to how WaveformAnalyzers write their results might be better -- register all fields before hand in RATDB, ensure that all branches are correctly created and filled even when such information is missing from a DSEvent.