numeric header include for std::accumulate to fix gcc600 error

[slava77]

recent builds in gcc 600 are failing with

RecoTracker/TkSeedGenerator/src/FastCircleFit.cc:56:34: error: 'accumulate' is not a member of 'std'
    const float invTotWeight = 1.f/std::accumulate(weight.begin(), weight.end(), 0.f);
                                  ^~~

added #include <numeric> to resolve the issue.
Afrer rebuilding RecoTracker/TkSeedGenerator and all other packages that failed linking in CMSSW_8_1_X_2016-05-13-2300 the cmsRun is functional again.

[cmsbuild]

A new Pull Request was created by @slava77 (Slava Krutelyov) for CMSSW_8_1_X.

It involves the following packages:

RecoTracker/TkSeedGenerator

@cmsbuild, @cvuosalo, @slava77, @davidlange6 can you please review it and eventually sign? Thanks.
@ghellwig, @makortel, @GiacomoSguazzoni, @rovere, @VinInn, @mschrode, @gpetruc, @dgulhan 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

[davidlt]

Yeah, I need to re-bootstrap GCC 6 branch. I will do that for the next week then it should be back and working.

[slava77]

@cmsbuild please test
@davidlt please clarify: is this PR useful?

[cmsbuild]

The tests are being triggered in jenkins.
https://cmssdt.cern.ch/jenkins/job/ib-any-integration/12989/console

[davidlt]

@slava77 it's useful.

[cmsbuild]

+1
Tested at: 214dae3
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14504/12989/summary.html

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-14504/12989/summary.html

[slava77]

+1

for #14504 214dae3

• jenkins tests pass

[cmsbuild]

This pull request is fully signed and it will be integrated in one of the next CMSSW_8_1_X IBs (tests are also fine). This pull request requires discussion in the ORP meeting before it's merged. @slava77, @davidlange6, @Degano, @smuzaffar

[davidlange6]

+1