Declared statics to be thread safe in MiniFloatConverter

The statics are filled at library load time but can't be made const
because of the complexity of filling arrays. We demark them as
thread safe to avoid the false positive from the static analyzer.
Reverted modules using TGraph::Fit back to legacy edm::Producer

ROOT's underlying implementation of TGraph::Fit is not thread safe
so we must avoid having more than one module calling it at one time.
The static analyzer determined the following code paths linking modules
to TGraph::Fit
ESRecHitProducer::produce();  ESRecHitWorkerBaseClass::run();  ESRecHitWorker::run();  ESRecHitFitAlgo::reconstruct() const;  ESRecHitFitAlgo::EvalAmplitude() const;  TGraph::Fit();
EcalUncalibRecHitProducer::produce();  EcalUncalibRecHitWorkerBaseClass::run();  EcalUncalibRecHitWorkerAnalFit::run();  EcalUncalibRecHitRecAnalFitAlgo<EBDataFrame>::makeRecHit();  TGraph::Fit();
in both cases, the module is linked to TGraph::Fit via a class which inherits
from a base class which the module uses. To fix this problem we either
1) wait till ROOT makes TGraph::Fit thread safe
2) drop the use of the inheriting class using TGraph::Fit.
Merge pull request #3622 from Dr15Jones/declareStaticsThreadSafeInMiniFloatConverter

Multithreading -- Declared statics to be thread safe in MiniFloatConverter
Merge pull request #3623 from Dr15Jones/revertModulesUsingTGraphFitToLegacy

Multithreading -- Reverted modules using TGraph::Fit back to legacy edm::Producer
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X