Protection for pt=0 ghost candidates in jet flavor clustering (62X_SLHC)

[ferencek]

Backport of #9186

[cmsbuild]

A new Pull Request was created by @ferencek (Dinko Ferencek) for CMSSW_6_2_X_SLHC.

Protection for pt=0 ghost candidates in jet flavor clustering (62X_SLHC)

It involves the following packages:

PhysicsTools/JetMCAlgos

@cmsbuild, @vadler, @nclopezo, @monttj can you please review it and eventually sign? Thanks.
@ferencek, @acaudron, @pvmulder, @imarches this is something you requested to watch as well.
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@fratnikov, @mark-grimes you are the release manager for this.
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[mark-grimes]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 6088613
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-9192/9532/summary.html

[mark-grimes]

merge