Convert HcalRealisticZS to stream module

[Dr15Jones]

The HcalRealisticZS uses the HcalDbService which the static analyzer
has complained about because of that object's use of the HCAL
conditions containers. However, upon further investigation the HcalDbService
is thread safe for this use. In addition, an upcoming change to
the conditions containers will solve the remaining thread unsafe uses
of those containers.
With that in mind, it is safe to convert HcalRealisticZS to a stream module.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_3_X.

Convert HcalRealisticZS to stream module

It involves the following packages:

SimCalorimetry/HcalZeroSuppressionProducers

@cmsbuild, @civanch, @nclopezo, @mdhildreth can you please review it and eventually sign? Thanks.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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@nclopezo, @ktf you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes or unless it breaks tests.

[cmsbuild]

+1
Tested at: c392ddd
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-6092/487/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_3_X IBs unless changes (tests are also fine). This pull request will be automatically merged.