[backport] Avoid rejecting good events in PythiaFilterMultiAncestor.cc

[rmanzoni]

PR description:

backport of #32449

[cmsbuild]

A new Pull Request was created by @rmanzoni (Riccardo Manzoni) for CMSSW_10_6_X.

It involves the following packages:

GeneratorInterface/GenFilters

@SiewYan, @mkirsano, @cmsbuild, @GurpreetSinghChahal, @agrohsje, @alberto-sanchez can you please review it and eventually sign? Thanks.
@alberto-sanchez, @mkirsano this is something you requested to watch as well.
@silviodonato, @dpiparo, @qliphy you are the release manager for this.

cms-bot commands are listed here

[SiewYan]

please test

[cmsbuild]

+1

Summary: https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-d2d738/11539/summary.html
CMSSW: CMSSW_10_6_X_2020-12-11-1100/slc7_amd64_gcc700

Comparison Summary

Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 34
• DQMHistoTests: Total histograms compared: 3214712
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3214377
• DQMHistoTests: Total skipped: 334
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 33 files compared)
• Checked 140 log files, 29 edm output root files, 34 DQM output files

[SiewYan]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_10_6_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_11_3_X is complete. This pull request will now be reviewed by the release team before it's merged. @silviodonato, @dpiparo, @qliphy (and backports should be raised in the release meeting by the corresponding L2)

[silviodonato]

+1