FIX in GBL reference trajectories: add missing initialisations

[mschrode]

Backport of #20262

Adds missing matrix initialisations to the EIGEN matrices.
This was not needed in previous implementation of GBL based on ROOT TMatrix
(ROOT presets matrices to 0., EIGEN not).

Fix provided by @ckleinw

[ghellwig]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/23077/console Started: 2017/09/19 16:27

[cmsbuild]

A new Pull Request was created by @mschrode (Matthias Schroeder) for CMSSW_9_3_X.

It involves the following packages:

Alignment/ReferenceTrajectories

@ghellwig, @arunhep, @cerminar, @cmsbuild, @franzoni, @lpernie can you please review it and eventually sign? Thanks.
@ghellwig, @mmusich, @tocheng, @tlampen this is something you requested to watch as well.
@davidlange6, @slava77 you are the release manager for this.

cms-bot commands are listed here

• Backported from FIX in GBL reference trajectories: add missing initialisations #20262

[ghellwig]

+1
provided jenkins agrees

[ghellwig]

type bugfix

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_3_X IBs after it passes the integration tests and once validation in the development release cycle CMSSW_9_4_X is complete. This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar (and backports should be raised in the release meeting by the corresponding L2)

[cmsbuild]

+1
Tested at: 1294458
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-20581/23077/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
9c60c7f
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-20581/23077/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-20581/23077/git-merge-result

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-20581/23077/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 differences found in the comparisons
• DQMHistoTests: Total files compared: 26
• DQMHistoTests: Total histograms compared: 2645486
• DQMHistoTests: Total failures: 206
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 2645091
• DQMHistoTests: Total skipped: 189
• DQMHistoTests: Total Missing objects: 0
• Checked 107 log files, 14 edm output root files, 26 DQM output files

[davidlange6]

merge