Preparing alternative e-map handling in unpacker for 73X

[abdoulline]

This is to allow for (an instance of) unpacker to use alternative emap (with appropriate label) with customized string
ElectronicsMap = cms.string("")
NB: default " " means regular GT tag.

Similar to what's submitted to 75X/74X -
#8600
#8610

[slava77]

@cmsbuild please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

A new Pull Request was created by @abdoulline for CMSSW_7_3_X.

Preparing alternative e-map handling in unpacker for 73X

It involves the following packages:

EventFilter/HcalRawToDigi

@cmsbuild, @cvuosalo, @nclopezo, @slava77 can you please review it and eventually sign? Thanks.
@Martin-Grunewald this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
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@nclopezo you are the release manager for this.
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[cmsbuild]

+1
Tested at: e046b2f
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8614/6970/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-8614/6970/summary.html

[cvuosalo]

+1

For #8614 e046b2f

This PR enables the unpacker to use an alternative emap. It doesn't yet change the emap used, so it should not change run-time behavior. This PR is nearly the same as #8610 for 74X and #8600 for 75X. #8610 has already been approved by Reco.

The code changes are satisfactory, and Jenkins tests against baseline CMSSW_7_3_X_2015-03-31-1400 show no significant differences, as expected.