Finally fix segfault!

[hroskes]

See details here: #6085

This fixes the segfault, and I think it addresses everyone's concerns there. Please let me know if not.

The summary histograms and the tree are filled in the endJob, as before, because they require the lower level histograms to be completely filled first, and it would be inefficient to reset every run. However, the structure (e.g. which histograms summarize which other histograms), which comes from the tracker topology, is set up at the beginning. In my tests I find identical output to setting the lastSetup variable.

This is orthogonal to #11022 except for one commit, which is rebased here to avoid conflicts.

[cmsbuild]

A new Pull Request was created by @hroskes (Heshy Roskes) for CMSSW_7_6_X.

Finally fix segfault!

It involves the following packages:

Alignment/OfflineValidation

@cmsbuild, @mmusich, @diguida, @cerminar can you please review it and eventually sign? Thanks.
@mschrode, @ghellwig, @frmeier, @mmusich, @tlampen 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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[mmusich]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 6d1b92b
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-11162/7918/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-11162/7918/summary.html

[diguida]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_6_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1