std::regex_replace not supported in gcc4.8.1

[wmtan]

A recent fix caused a compilation error in gcc4.8.1 because std::regex_replace() does not appear to be supported there. This pull request simply replaces this use of std::regex with boost::regex.

[cmsbuild]

A new Pull Request was created by @wmtan for CMSSW_7_4_X.

std::regex_replace not supported in gcc4.8.1

It involves the following packages:

FWCore/Utilities

@cmsbuild, @Dr15Jones, @ktf, @nclopezo can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @wddgit this is something you requested to watch as well.
You can sign-off by replying to this message having '+1' in the first line of your reply.
You can reject by replying to this message having '-1' in the first line of your reply.
If you are a L2 or a release manager you can ask for tests by saying 'please test' in the first line of a comment.
@Degano you are the release manager for this.
You can merge this pull request by typing 'merge' in the first line of your comment.

[Dr15Jones]

please test

[Dr15Jones]

+1

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes or unless it breaks tests. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @ktf, @smuzaffar

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_7_4_X IBs unless changes or unless it breaks tests. This pull request requires discussion in the ORP meeting before it's merged. @davidlange6, @Degano, @ktf, @smuzaffar

[cmsbuild]

+1
Tested at: e1f99f9
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-7635/2477/summary.html