SiStripClusterizer: veto zero-charge clusters

[pieterdavid]

See the discussion in #13945 : zero-charge clusters get a NaN position error from the CPE, which leads to a segmentation fault in the reconstruction.
Fixed by changing the value of (HLT)SiStripClusterChargeCutNone from -1 to 0 (it is compared using ">" in https://github.com/cms-sw/cmssw/blob/CMSSW_8_1_X/RecoLocalTracker/SiStripClusterizer/src/ThreeThresholdAlgorithm.cc#L85)

[cmsbuild]

A new Pull Request was created by @pieterdavid (Pieter David) for CMSSW_8_1_X.

It involves the following packages:

HLTrigger/Configuration
RecoLocalTracker/SiStripClusterizer

@perrotta, @cmsbuild, @silviodonato, @cvuosalo, @fwyzard, @Martin-Grunewald, @slava77, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @makortel, @forthommel, @yduhm, @GiacomoSguazzoni, @gbenelli, @rovere, @VinInn, @nickmccoll, @jlagram, @jalimena, @gpetruc, @OlivierBondu, @threus, @geoff-smith this is something you requested to watch as well.
@slava77, @smuzaffar you are the release manager for this.

cms-bot commands are listed here #13028

[Martin-Grunewald]

-1
HLT menu dumps are never modified directly.
Please code a customisation function to be added in HLTrigger/Configuration/python/customizeHLTforCMSSW.py

[makortel]

Could you add a comment explaining that the value must not be less than zero (and the reason for that)? Thanks.

[rovere]

Hi all,
I have a very vague recollection of the problem, but in general I would not use side-effects (the CCC) to fix local-reco problems. If clusters with 0 charge are a problem, we should get rid of them explicitly in local-reco, not as a side-effect of CCC (like you seem to imply here, since -1 meant no cut, while your proposal means 0 is always a valid cut)

[pieterdavid]

I'm sorry, I had not realised that SiStripClusterChargeCutNone is also used for other things than the CCC in the clusterizer, so just changing that may also introduce problems elsewhere. I will close this pull request and prepare a new one with a modification to the clusterizer itself, as Marco suggested.