use more intuitive names for FlavourTagsMerger inputs and outputs
just a little cleanup
goes with LHCb!4533 DaVinci!1048 LHCbIntegrationTests!69 !3799 Moore!3343
just a little cleanup
goes with LHCb!4533 DaVinci!1048 LHCbIntegrationTests!69 !3799 Moore!3343