DataFormats/SiPixelDetId: fix for undefined unordered_map when compiling with clang 4.0.1 and macos10.9.X SDK under Conda

[gartung]

Adding this #include allows this to compile under Conda which uses clang4.0.1 and macOS10.9.x SDK.

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-26708/9693

• This PR adds an extra 12KB to repository

[cmsbuild]

A new Pull Request was created by @gartung (Patrick Gartung) for master.

It involves the following packages:

DataFormats/SiPixelDetId

@cmsbuild, @civanch, @mdhildreth can you please review it and eventually sign? Thanks.
@makortel, @rovere, @VinInn this is something you requested to watch as well.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[gartung]

@smuzaffar This is the other change I had to make to compile under Conda.

[civanch]

please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-run-pr-tests/122/console Started: 2019/05/09 13:10

[cmsbuild]

+1
Tested at: d8368f7
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-44dc92/122/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-44dc92/122/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 4 differences found in the comparisons
• DQMHistoTests: Total files compared: 33
• DQMHistoTests: Total histograms compared: 3211964
• DQMHistoTests: Total failures: 1
• DQMHistoTests: Total nulls: 0
• DQMHistoTests: Total successes: 3211759
• DQMHistoTests: Total skipped: 204
• DQMHistoTests: Total Missing objects: 0
• DQMHistoSizes: Histogram memory added: 0.0 KiB( 32 files compared)
• Checked 137 log files, 14 edm output root files, 33 DQM output files

[civanch]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next master IBs (tests are also fine). This pull request will now be reviewed by the release team before it's merged. @davidlange6, @slava77, @smuzaffar, @fabiocos (and backports should be raised in the release meeting by the corresponding L2)

[fabiocos]

+1