Cleanup PluginManager to avoid StaticAnalyzer warnings

[Dr15Jones]

The remaining statics in the PluginManager are protected by various mutex so are thread safe. Added the appropriate C++11 attribute to let the StaticAnalyzer know the code is fine.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_1_X.

Cleanup PluginManager to avoid StaticAnalyzer warnings

It involves the following packages:

FWCore/PluginManager

@cmsbuild, @Degano, @Dr15Jones, @ktf, @nclopezo can you please review it and eventually sign? Thanks.
@wmtan this is something you requested to watch as well.
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@nclopezo, @ktf you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[Dr15Jones]

+1

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs unless changes or unless it breaks tests. @nclopezo, @ktf can you please take care of it?

[nclopezo]

+1
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-3183/766/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs unless changes (tests are also fine). @nclopezo, @ktf can you please take care of it?

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-3183/766/summary.html

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_1_X IBs unless changes (tests are also fine). @nclopezo, @ktf can you please take care of it?