Fix crash in tracking MC validation plot scripts

[makortel]

This PR fixes an assert-style exception in tracking MC validation plot scripts. The scripts worked with the same input in 810, so maybe there was some change in ROOT that allows these histogram to extend their x axis (leading to additional surprise-bins later). The fix is to explicitly disable the axis extension.

Thanks to @rovere for reporting the issue.

Tested in 9_0_0_pre2, no changes expected in standard workflows.

@rovere @VinInn

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/17140/console Started: 2016/12/21 17:01

[cmsbuild]

A new Pull Request was created by @makortel (Matti Kortelainen) for CMSSW_9_0_X.

It involves the following packages:

Validation/RecoTrack

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

cms-bot commands are listed here #13028

[cmsbuild]

+1
Tested at: d97bfeb
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17091/17140/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-17091/17140/summary.html

[dmitrijus]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_9_0_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @smuzaffar

[davidlange6]

+1