Remove std::move's preventing copy elision from return statements

[makortel]

PR description:

This PR suggests to remove std::move's from return statements that currently prevent the compiler from eliding the copy/move altogether. These were found by GCC 9.

PR validation:

The code compiles without warnings with GCC 9.

[cmsbuild]

The code-checks are being triggered in jenkins.

[cmsbuild]

+code-checks

Logs: https://cmssdt.cern.ch/SDT/code-checks/cms-sw-PR-26554/9454

• This PR adds an extra 16KB to repository

[cmsbuild]

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

It involves the following packages:

RecoTauTag/RecoTau

@perrotta, @cmsbuild, @slava77 can you please review it and eventually sign? Thanks.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[makortel]

@cmsbuild, please test

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/34376/console Started: 2019/04/26 22:44

[cmsbuild]

+1
Tested at: 0bc325f
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-26554/34376/summary.html

[cmsbuild]

Comparison job queued.

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-26554/34376/summary.html

Comparison Summary:

• No significant changes to the logs found
• Reco comparison results: 0 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

[perrotta]

+1

• Technical
• Jenkins tests pass

[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