Add HO particle flow changes to the run2 era

[mark-grimes]

Adds the Run 2 customisations from customisePostLS1 relevant to the HO particle flow changes. No changes are made unless the run2 era is explicitly activated.

Testing has been limited. I just checked that the particular modules have the changes applied when the era is activated. If it's not activated then there is no change. I'll worry about ensuring identity between the two methods (customisation versus era) once all the pull requests are in.

I haven't taken the customisations out of the run2 helper function customiseRun2EraExtras. The postLS1Customs.py file is being heavily modified by #7579, and this would likely cause a conflict. Applying the modification twice has no harm so I'll remove those lines in a later pull request.

[cmsbuild]

A new Pull Request was created by @mark-grimes (Mark Grimes) for CMSSW_7_4_X.

Add HO particle flow changes to the run2 era

It involves the following packages:

RecoParticleFlow/PFClusterProducer

@cmsbuild, @cvuosalo, @nclopezo, @slava77 can you please review it and eventually sign? Thanks.
@mmarionncern, @bachtis, @lgray this is something you requested to watch as well.
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@Degano you are the release manager for this.
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[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: bd4976e
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7675/2517/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7675/2517/summary.html

[davidlange6]

bypassing era PRs - lets discuss once Mark has the full set implemented - currently they have no effect