Calo not working with Run2Support/DetDesc

@gcorti @sponce

The following discussion from !32 (merged) should be addressed:

@mimazure started a discussion: (+4 comments)
@sponce

I just tried running a simulation job with calorimeters/2016 with DetDesc on Run2Support and I get the following error:
```
get():: No valid data at '/dd/Structure/LHCb/DownstreamRegion/Prs'
```
The same configuration for DetDesc on LHCb works correctly. Is this expected?