Missed a needed T*::Fit change for thread safety

[Dr15Jones]

In a previous commit which changed calls to T*::Fit to be the thread
safe form, one call was missed.
This was found by the new static analyzer update.

This has been sitting in my repository for months becuase I forgot to do a pull request.

[cmsbuild]

A new Pull Request was created by @Dr15Jones (Chris Jones) for CMSSW_7_6_X.

Missed a needed T*::Fit change for thread safety

It involves the following packages:

DQM/BeamMonitor

@cmsbuild, @danduggan, @deguio can you please review it and eventually sign? Thanks.
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

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

+1
Tested at: 12e35f9
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10949/7662/summary.html

The following merge commits were also included on top of IB + this PR after doing git cms-merge-topic:
aff6fe4
7c0314a
2423f1a
8ed8251
bd64880
You can see more details here:
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10949/7662/git-log-recent-commits
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10949/7662/git-merge-result

[cmsbuild]

Comparison is ready
https://cmssdt.cern.ch/SDT/jenkins-artifacts/pull-request-integration/PR-10949/7662/summary.html