Added VeloBackward case to update_states.
Required by Moore!2157 (merged), Allen!1124 (merged).
Needed for VeloBackward input lists. Discovered by using a VeloBackward v3::Tracks container as input to LHCb::Converters::Track::v1::ConvFromV3TrackV1Track
(fromV3TrackV1Track
).
Edited by Patrick Spradlin