Fix unpacker instance name
Looks like an update was made which caused the name of the unpackers to include a ., and have a useless HltSourceID in the instance name. So this is a good time to finally fix this as mentioned in the FIXME comment. The result is that eg.
Unpack_HltSourceID.Hlt2__Event_HLT2_Hlt2SLB_XibminusToXic0TauNu_Xic0TopKKPi_TauToMuNuNu_Particles
will change into
Unpack_Event_HLT2_Hlt2SLB_XibminusToXic0TauNu_Xic0TopKKPi_TauToMuNuNu_Particles
which completely removes the redundant HltSourceID.Hlt2 as that is actually derived from the `/Event/HLT2' prefix of the path
Edited by Gerhard Raven