Add additional Error messages for TFile reading

[Dr15Jones]

Have all causes for a TFile::ReadBuffer failure report an Error
message. This will help in debugging site problems.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for master.

It involves the following packages:

IOPool/TFileAdaptor

@cmsbuild, @smuzaffar, @Dr15Jones, @davidlange6 can you please review it and eventually sign? Thanks.
@wddgit this is something you requested to watch as well.
@davidlange6 you are the release manager for this.

cms-bot commands are listed here

[Dr15Jones]

@bbockelm please review

[Dr15Jones]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/21590/console Started: 2017/07/18 22:59

[bbockelm]

Looks good to me. Seems that it would improve error messages; can't think of any downsides right now.

[bbockelm]

@Dr15Jones - fwiw, you should be able to suggest / assign me as a reviewer using the GitHub UI; no need to request it in the comments. That allows me to better see all the open review requests across projects.

[Dr15Jones]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs after it passes the integration tests. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @smuzaffar

[cmsbuild]

+1
Tested at: 183f57d
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-19809/21590/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
504de00
f83119a
3f5ebf2
c8e722e
6d67a00
b8eb517
d6a4f02
9accd33
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-19809/21590/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-19809/21590/git-merge-result

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-19809/21590/summary.html

Comparison Summary:

• No significant changes to the logs found
• ROOTFileChecks: Some differences in event products or their sizes found
• Reco comparison results: 1242 differences found in the comparisons
• DQMHistoTests: Total files compared: 23
• DQMHistoTests: Total histograms compared: 2281784
• DQMHistoTests: Total failures: 39407
• DQMHistoTests: Total nulls: 475
• DQMHistoTests: Total successes: 2241736
• DQMHistoTests: Total skipped: 166
• DQMHistoTests: Total Missing objects: 0
• Checked 93 log files, 14 edm output root files, 23 DQM output files

[davidlange6]

+1