Add missing <cmath> header and remove <string.h> header

[davidlt]

The following errors are reported by GCC (6.0.0, r233941):

Utilities/StorageFactory/src/StatisticsSenderService.cc:82:191: error: 'sqrt' was not declared in this scope
Utilities/StorageFactory/src/StatisticsSenderService.cc:90:191: error: 'sqrt' was not declared in this scope

Signed-off-by: David Abdurachmanov David.Abdurachmanov@cern.ch

[cmsbuild]

A new Pull Request was created by @davidlt for CMSSW_8_1_X.

It involves the following packages:

Utilities/StorageFactory

@cmsbuild, @smuzaffar, @Dr15Jones, @davidlange6 can you please review it and eventually sign? Thanks.
@Martin-Grunewald, @wddgit this is something you requested to watch as well.
@slava77, @Degano, @smuzaffar you are the release manager for this.

cms-bot commands are list here #13028

[cmsbuild]

+1
Tested at: cf9c6b6
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13614/11739/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
7e238c0
76fc09b
f6463e3
c7f47ce
93f1c24
7bbd188
3138a01
9217ea5
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13614/11739/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13614/11739/git-merge-result

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-13614/11739/summary.html