Fix ME0 neutron background normalization

[calabria]

In this PR:

• Default digitizer: new parameter to rescale the neutron background also for the new beam pipe effect
• Default digitizer: new neutron background normalization to 7.5x10^35 Hz/cms^2 (PU200) + safety factor of 2 (new beam pipe)
• Re-digitizer: the same parameters (instLumi of the default digitizer and the rate safety factor) are introduced here. They depend from the value of the default digitizer in order to throw away the correct fraction of background hits and reproduce the desired rate
  @jshlee @pietverwilligen @kpedro88 @dildick

[cmsbuild]

A new Pull Request was created by @calabria (Cesare) for CMSSW_9_0_X.

It involves the following packages:

SimMuon/GEMDigitizer

@cmsbuild, @civanch, @mdhildreth, @davidlange6 can you please review it and eventually sign? Thanks.
@jhgoh 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

[kpedro88]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/17120/console Started: 2016/12/19 19:39

[cmsbuild]

+1
Tested at: 5d3e708
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17078/17120/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17078/17120/summary.html

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @smuzaffar

[davidlange6]

+1