94X backport: Fix GenParticles2HepMCConverter to run on herwig samples

[jhgoh]

This is backport of #21349
also read cms-nanoAOD#82

@arizzi @intrepid42

[cmsbuild]

A new Pull Request was created by @jhgoh (Junghwan John Goh) for CMSSW_9_4_X.

It involves the following packages:

GeneratorInterface/RivetInterface

@cmsbuild, @efeyazgan, @perrozzi, @thuer, @govoni can you please review it and eventually sign? Thanks.
@alberto-sanchez, @agrohsje, @mkirsano this is something you requested to watch as well.
@davidlange6, @slava77 you are the release manager for this.

cms-bot commands are listed here

[perrozzi]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/24700/console Started: 2017/11/27 16:13

[cmsbuild]

+1
Tested at: 297be5a
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-21467/24700/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
9620e95
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-21467/24700/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-21467/24700/git-merge-result

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-21467/24700/summary.html

There are some workflows for which there are errors in the baseline:
10024.0 step 5
10824.0 step 5
11624.0 step 5
The results for the comparisons for these workflows could be incomplete
This means most likely that the IB is having errors in the relvals.The error does NOT come from this pull request

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 25
• DQMHistoTests: Total histograms compared: 2306583
• DQMHistoTests: Total failures: 42
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2306381
• DQMHistoTests: Total skipped: 160
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0 KiB( 0 files compared)
• Checked 102 log files, 8 edm output root files, 25 DQM output files

[perrozzi]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_4_X IBs (tests are also fine) and once validation in the development release cycle CMSSW_10_0_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar (and backports should be raised in the release meeting by the corresponding L2)

[davidlange6]

+1