Fix a small bug in tracking validation scripts

[makortel]

This PR fixes a small bug that slipped in in #12666 (the generated "Out of the box" page gets screwed up).

Tested in CMSSW_8_0_X_2015-12-07-1100. Should have no effect on standard workflows.

@rovere @VinInn

[cmsbuild]

A new Pull Request was created by @makortel (Matti Kortelainen) for CMSSW_8_0_X.

It involves the following packages:

Validation/RecoTrack

@cmsbuild, @vanbesien, @deguio, @davidlange6 can you please review it and eventually sign? Thanks.
@GiacomoSguazzoni, @rovere, @VinInn, @cerati, @wmtford, @istaslis, @dgulhan this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

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[VinInn]

@cmsbuild , please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/10194/console

[cmsbuild]

+1
Tested at: 8bca100
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-12706/10194/summary.html

[deguio]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @Degano, @smuzaffar