Clear up warnings about missing containers in simulation jobs
This should fix warnings of the following type in the simulation output:
INFO OutputStreamHITS.OutputStreamHITS_TopFolder 3 2 WARNING add: can not find type [JetCollection] in clid db
INFO OutputStreamHITS.OutputStreamHITS_TopFolder 3 2 WARNING add: can not find type [xAOD::JetContainer] in clid db
when the containers are not present.